The first joint meeting of the French Society for Developmental Biology and the French Society of Genetics took place close to Avignon, in Isle sur la Sorgue, between the 12th and the 15th of November. This small meeting was a great chance to hear about the interesting developmental biology going on in France, and to talk with the scientists in the French community. The conference venue- a nice holiday resort away from the centre of Avignon- was ideal for this, encouraging people to stay in the venue and interact during the breaks.

Joint meetings are very interesting, as they highlight the overlap and synergy between fields. The connections between developmental biology and genetics were highlighted, for example, in the first opening lecture, by Patrick Lemaire (CRBM, Montpellier). His lab is attempting to understand how different ascidian species can have very similar morphologies and developmental stages while diverging in genome sequence, by comparing genome architecture and regulatory sequences across species.

The next 2 days of the conference were divided into different sessions. It is not possible to summarise all the talks, so I will highlight only a few. The first session was on the epigenetics of development. One of the highlights in this session was the talk by Olivier Voinnet (ETH Zurich) who considered how plants are able to silence transposons by analyzing the behavior of the reactivated transposon Évadé. He showed how Évadé is perceived as an RNA virus by the plant, but is able to evade silencing until a threshold of the virus RNA is reached, leading to promoter methylation and silencing. The second session of the conference was on germ cells, meiosis and early developmental decisions. In this session, Jean René Huynh (Institute Curie) explored how chromosome pairing takes place in meiosis in Drosophila, while Marine Poulain (INSERM CEA) presented her work investigating the role of DMRTA2 in the female ovaries using xenografts of human fetal ovaries in mice.

The second full day of the conference kicked off with a session on genome dynamics and evolution. In this session Jean Deutsch (UPMC CNRS) used his slot for a philosophical discussion of why we must revisit the traditional definition of ‘gene’ in light of the discoveries in the last few decades. Jean has written an article about this topic for the French edition of Scientific American, which you can read here [in French]. Also in this session, Guillaume Balavoine (Institut Jacques Monod) introduced the marine annelid Platynereis as an interesting model system in which to study segmentation, while Nicolas Gompel (LMU Munich) explored the genetics behind the emergence and diversification of wing patterns in Drosophila.  In the Signalling and Gene network sessions, Corinne Houart (King’s College London) presented her group’s work.on the signaling centres involved in regulating the size and complexity of the forebrain. Also in this session Pierre Leopold (IBV Nice) considered how organ growth and developmental timings are coordinated in Drosophila.

The last day of the conference started with a talk by Emmanuelle Szenker, the winner of the French Society for Developmental Biology PhD Thesis Award, who examined the roles of histone variants H3.2 and H3.3 during frog development during her PhD.

The conference concluded in style with 3 great talks in a session dedicated to new approaches and challenges in development and genetics. Frank Schnorrer (MPI Munich) presented work from his lab investigating how flight muscle morphogenesis takes place, using a combination of techniques, including beautiful microscopy, RNAi and microarrays. He also introduced his current collaborative project to generate a comprehensive, genome-wise library of tagged Drosophila proteins within their native genomic context. Eileen Furlong (EMBL Heidelberg) described how her lab is assessing the 3D organization of enhancers in the genome, and how these physical connections change during development. The conference concluded with an excellent talk by Feng Zhang (MIT). Feng first described the development and applications of CRISPR technology. He then moved on to present a new method to control epigenetic states by combining optogenetics technology with the microbial effector proteins TALEs.
 
It was great to attend this meeting and to be able to get a taste of the great science going on in France. We hope to have spread the word about the Node a little bit more, and hopefully have a greater participation of the French community on the Node in the future!

(4 votes)

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What is a science exhibition?

These are publicly accessible exhibitions that hold stalls designed to communicate specific areas of science to a lay audience. They tend to vary in terms of their content and the groups of people they are intended to engage with but will usually involve a series of organised events and stalls that communicate specific areas of science. One of the most widely known and well attended of these exhibitions is the The Royal Society Summer Science Exhibition. This is a week-long event with scientists from across the UK showing off some amazing work from all fields of science at the Royal Society in London. My personal highlights from this year were learning that a t-rex had feathers, that I’m not smarter than a zebra fish and just what on earth the Higgs boson actually is.

We were lucky enough to be granted the opportunity to show some of our work at this year’s exhibition and our stall was:

http://sse.royalsociety.org/2013/exhibits/biology-builders/

These types of exhibitions are designed to be fun, interactive and educational, demonstrating the amazing range and quality of science being performed in the UK. It is not only the physical stalls themselves that the public come to see but you, the person actually doing the work. Putting a face to the science is the best way to showcase it and the interactions that you have with the public can be some of the most rewarding you will ever have in your carrier.

Why are these events important?

First and foremost these events are about feeding back to the people who fund your work, the general public. The majority of the work we do as academic scientists is funded from public money in the form of taxation or donation and as the financiers these people have the right to know what their money is being spent on; and science exhibitions are designed to do just that. Communicating science to the general public is also becoming increasingly important to funding bodies and many are beginning to require public engagement strategies to be written into grant applications.

The personal experience of doing these events is highly rewarding and all members of our stall team thoroughly enjoyed the experience. Speaking with the public can give you a fresh perspective on what you do as well as reinforce to you as a person how important and valuable your work really is. We even had staff and students fighting over shifts so they could spend as much time on the stall as possible.

Some of the most valuable interactions we experienced involved young people and school groups. These young adults showed an incredible level of knowledge and enthusiasm not only for the science we discussed but us as scientists. This event provided an amazing opportunity to educate and inspire the next generation of scientist, breaking down the stereotypes of who scientists really are and what we do.

Getting started

The Royal Society Summer Science Exhibition is one of the biggest and most prestigious science outreach events in the UK and so when we first began to plan our stall we realised how important it would be to get experience with these types of events. We therefore decided to show a very simple stall at our Universities annual public outreach day called Mayfest. The experiences we gathered from this provided invaluable feedback on the basic design of our stall at the Royal Society and enabled us to try out a variety of different interactive elements to all age groups.

Even if you intend to only hold a small stall at such a local event it is always worth gaining some practical experience in speaking to the general public about your science before you hold your stall. Most organisations have some form of public outreach experience and it is worth seeking out those who run these activates within your institution. The best advice would of course be from someone who has run a stall of this kind but any advice or guidance they can offer would be invaluable.

There are many different aspects to running a stall of this kind ranging from design and construction to safeguarding vulnerable people during interactions with the public. Form an enthusiastic and hardworking team of people who work well together and most importantly plan meticulously. We were lucky enough to have a healthy budget for our exhibition stand but you can run a stall with almost any budget – you will amazed what you can beg and steal – but you can also seek funding from external sources.
 
 
Here are some links to UK based grant opportunities:

    Welcome Trust: http://www.wellcome.ac.uk/Funding/Public-engagement/index.htm

    EPSRC and BBSRC: No longer have separate calls as they now require engagement within existing grant calls so speak to PI’s within your organisation about how a stall could satisfy their grant stipulations. They may be persuaded to part with some cash as a result.

    Science and Technology Facilities Council: http://www.stfc.ac.uk/1780.aspx

    Society for Applied Microbiology: http://www.sfam.org.uk/en/grants–awards/public-engagement-grant.cfm

    The Physiological Society: http://www.physoc.org/public-engagement-grants

    Institute of Physics: http://www.iop.org/about/grants/outreach/page_38843.html

    British Society for Plant Pathology: http://www.bspp.org.uk/funds/promotion.php

    British Ecological Society: http://www.britishecologicalsociety.org/grants-awards/outreach-grants/

    Biochemical Society: http://www.biochemistry.org/Grants/EducationalGrants/ScientificOutreachGrants.aspx

Designing and building the stall for your audience

When we sat down and began to decide what the stall would be like the central questions we asked ourselves were; ‘what message are we trying to convey’ and ‘who are we delivering this message too’. The Royal Society exhibition covers all age ranges, from parents with very young children through to informed retired professionals visiting for the day and guided school groups. In terms of our message we had quite a complicated idea that would use three current technologies to demonstrate biological complexity during early development and how this could be rebuilt in a laboratory for future clinical therapies. You could have designed an entire stall around each of these but we decided to simplify and link them into a cohesive and exciting experience for the visitor.
 

Our stall ultimately consisted of a 3D printer in the central podium that produced large scale biological structures, allowing visitors to see the machine in action and interact with the printed objects. The podium to the left of the printer consisted of a microscope that allowed the visualisation of stem cells patterned using protein stencil technology. The third and final podium showed a live link to our laboratory in Nottingham allowing member of the public to position live stem cells using an optical tweezer system with the click of a mouse.

Once we knew who we were pitching at and the message we wanted to convey the next question was ‘how do we design the stall to deliver this message to all age ranges’. This was a real challenge particularly as the work we were trying to show covered everything from the physics of lasers to what a stem cell is. We rapidly realised that you cannot cover everything and that it may be necessary to sacrifice detail so that all visitors can have a fun and interesting experience whilst leaning something new about our science. Consequently the basic design was very simple with three podiums displaying the three technologies we were displaying with more detailed, simpler interactive objects to hand so that we could adapt to all age ranges and leaning abilities depending on need.

Would we recommend running a stall?

Absolutely! When we started this process we had never run a stall of this kind and the majority of the people who ultimately staffed the stall had never done any form of public engagement. Everyone thoroughly enjoyed the experience and if we can do it anyone can, so we would absolutely encourage all scientists to participate in science exhibitions.

 
 
Also read Glen’s outreach activity suggestion- Using modified ping-pong balls to demonstrate early embryogenesis and embryonic stem cell activity
 

This post is part of a series on science outreach. You can read the introduction to the series here and read other posts in this series here.

(1 votes)

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Why is this a good activity?

It is often difficult to communicate how the organization of individual cells can affect later function, particularly with regard to early embryogenesis and the organization of embryonic stem cells. This activity allows a simple way of visualizing these processes to all age groups from any educational background. The activity is also fully interactive and is relatively inexpensive.

 Which age group is this activity aimed at:

Any age group but is particularly useful for younger audiences.

Materials needed:

Ping-pong balls of at least two different colors and adhesive Velcro spots both hooks and loops.

Step-by-step instructions:

Take a ping pong ball and stick 4 adhesive Velcro hook spots on opposing sides, around the circumference. Then stick 2 adhesive loop spots on the remaining, opposing sides. On a new pin-pong ball do the same but use 4 x loops and 2 hooks. Repeat this process as many times as desired so that there are an equal number of each type of ball. You can also mix in different colored balls to represent cells at differing stages of development.

You can use these to illustrate how individual cells are organized in early embryonic structures by allowing your audience to build a 4 or 8 cell structure themselves as you explain the concepts. These aids are also useful when explaining embryonic stem cell aggregate structures and also how at different stages of development groups of differing cells can be organized into specific locations (colored ping-pong balls).
 
 

Tips

You can use these as a visual aid to describe principles to older audiences and give them to younger children to both entertain but also convey basic principles such as cell adhesion and cell organization. Make a lot of these as they tend to go missing.

 
 
Also read Glen’s post about the Biology Builders stand at the Royal Society Summer Science Exhibition, a great case study for science outreach at science festivals.
 

This post is part of a series on science outreach. You can read the introduction to the series here and read other posts in this series here.

(2 votes)

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Usain Bolt may be the fastest man alive, but which is the fastest cell? Since 2011 that the World Cell Race has been trying to answer this question. The motivation behind the competition is not only to find the fastest cell, but also to understand and discuss cell mobility. Cell movement is very important during development and the normal functioning of the organisms, but it can have very dramatic consequences when it goes astray, such as during metastasis in cancer.

Speed is not everything in this competition. The cells will need not only to be the fastest, but they also need to be ‘smartest’, as they will race through micro-fabricated mazes. Several labs around the world have submitted their best cell lines, and the overall winner will receive a 400 euros prize.

This year’s race is happening today (22nd of November) at 6pm GMT (1pm EST). The Race is taking place in Boston, at the BioMEMS Resource Center, and has been organized in collaboration between groups at Massachusetts General Hospital and Institute Curie in Paris. You can follow all the action on the World Cell Race website.

Let the fastest (and smartest) cell win! And if you enjoy this year’s competition, why not consider sending your fastest cells to participate in next year’s World Cell Race?

(3 votes)

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Hi I’m Steve and I work in the Sensory Development lab at the RIKEN Center for Developmental Biology in Kobe, Japan. We study the development of the chick inner ear. I haven’t always been in a chick lab – during my Ph.D. at The University of York I used Xenopus, so it was really nice to read Gary’s post. Looking back, I miss those slimy yet serene critters. Although at the time (as a poor PhD student) I would often get pretty jealous of all the care, attention, and, in particular, premium food they used to get. Especially when I was tucking into my staple Ph.D. meal, the supernoodle sandwich™. Anyway, enough of the reminiscing!
 

Chick-en you believe it?

The chick is a brilliant and beautiful model system for studying the embryonic development, and in our case more specifically, the inner ear. Embryo husbandry could not be simpler, because the hen is thoughtful enough to pack everything the embryo needs to develop inside the egg. We simply buy fertilized eggs from a local farm, incubate them at 37°C, and hey presto, the embryos develop!
 

It takes 21 days for chicks to hatch, but luckily we don’t have to wait that long if we need chicks, because we can also order 20 day-old fertilized eggs that arrive ready to hatch. When hatching, the chick cuts through the top of the shell using its “egg tooth” and then shimmies out. This takes a lot of work, so the chicks are pretty exhausted afterwards and they often take a little nap. But once they recover they are soon up and at ‘em, hopping around and pecking for food.

Our hatched chicks reside in a special bird room where they live in large temperature controlled incubators complete with sawdust and shredded paper bedding, fresh clean water, and mix of cereal and seed for food. They get fresh bedding, food and water every day, and we are lucky to have a very attentive technician (she calls herself “Mama Hen”) who takes care great of them.

Access all areas.

Because chick embryos develop ex-utero, we have easy access to them from the very earliest stages of development. We put a small strip of sellotape along the shell, cut a window through it, and can access the embryo through this window as it develops on the surface of the yolk. This unlimited access is fantastic for us, because the inner ear is specified very early in development. To understand how these events occur, we need to be able to manipulate the system at these early stages. The chick system makes it easy to do so.
 

Spot the difference.

Mice are the kings when it comes to using a model system close to humans. So why bother using other systems at all? Well, one reason is that the differences between species can be just as important as the similarities. Birds, unlike mammals, can regenerate the hair cells of their inner ear, so for our lab this makes them a great system to use for researching the mechanisms that govern regeneration. We use hatched chicks up to around 3 weeks old to study regeneration. By focusing on the differences as well as they similarities between species we can gain an insight into what exactly are the key mechanisms that coordinate the regenerative process.
 

An egg-sample day – the morning.

Ok, no more puns, I promise. The first thing I do when I arrive in the morning is check the embryos already incubating from previous day’s experiments. It is important to keep the incubator as clean as possible, so we keep a keen eye out for any signs of infection and remove the offending eggs.

Next I will check to see if any fresh fertilized eggs have arrived for me. If so, I put them in a 14°C fridge. This arrests the embryos’ development, and allows me to have a better idea of their developmental time course when I come to incubate them at 37°C. Accurate timing is everything because we don’t have near limitless supplies of eggs. We receive egg deliveries twice a week, and you have to order your eggs a week in advance, so forward planning is critical. If you miss the stage you want, you have to wait until next weeks eggs arrive to start again.

After this, I usually start some electroporation experiments. I like to do these in the morning, for two reasons. Firstly, I am usually electroporating something that is GFP or RFP tagged, so a morning session means I can check for fluorescence just before I go home in the evening. Secondly, the ever-approaching lunchtime serves as good motivation to work quickly.

Our electroporation set up is in the main area of our lab, near to a gargantuan egg incubator and a darkroom for fluorescent microscopy. A common and somewhat surreal result of this set up is that I often find myself chatting with someone who has their head (and often most of their upper body) inside the incubator as they check their eggs. To increase the surreal stakes further, what appears to be a dismembered head will often join the conversation when someone who is working in the dark room sticks their head around the curtain to get involved. And of course I’m trying to talk with a mouth pipette for the electroporations in my mouth. Despite (or maybe because of) this, it is one of my favourite areas of the lab.
 

The afternoon

The afternoons are spent doing a variety of things, depending on what stage of the project I am at and what the priorities are. Often I am finishing up ongoing experiments, – doing some immunohistochemistry, some confocal microscopy, analyzing data, administering drug treatments, fixing samples, or doing some in situ hybridisations. Actually, on the subject of in situ’s, we have an “in situ robot”, which runs through most of the protocol autonomously, leaving us with the job of overseeing the final colour reaction. I’m pretty skeptical about this robot – something about which the rest of the lab enjoy mercilessly taking the mickey out of me. But I’ve seen the Terminator movies, and I know what happens when robots get too smart. This one hasn’t done anything other than produce beautiful gene expression patterns yet, but it is only a matter of time.

The day ends incubating some more eggs for the next set of experiments. This is probably the most dangerous time of the day for me. The fridge and the incubator are at opposite ends of the lab, so I run a nightly gauntlet from one to the other, precariously tippy toeing through the busy lab with trays of eggs in my hands. Each tray carries 24 eggs, and when you drop one (as I have many times over the years) it really sucks!

This post is part of a series on a day in the life of developmental biology labs working on different model organisms. You can read the introduction to the series here and read other posts in this series here.

(13 votes)

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Ever wondered how cells communicate with each other during brain development? What happens to cells which the body doesn’t need any longer? And how do scientists study the events that are going on inside the brain?

In the upcoming ELLS Webinar, EMBL group leader Francesca Peri looks at the brain’s phagocyting cells – the microglia – and explores how the newest imaging techniques help scientists to understand how the developing brain is protected from damage and injury.

To read more, watch the Webinar teaser and register for the FREE event, please follow this link.

27th November 2013, 4:00 – 5:00 pm CET

Topic: “Neuronal cell death goes live: microglia as the guardians of the developing brain”

Speaker: Francesca Peri, EMBL Group Leader

Organised by the European Learning Laboratory for the Life Sciences

(2 votes)

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Using Drosophila melanogaster, researchers at IRB Barcelona discover that during multiple cell migrations a single cell can act as leader, dragging the others with it.
_____________

The migration of groups of cells in order to form tissues is common during the development of an organism. Discovering how these multiple movements are achieved is not only crucial to understand the basic principles of development but provides new information and insights for further research into processes associated with the spread of cancer.

Jordi Casanova, head of the “Morphogenesis in Drosophila” lab at IRB Barcelona and CSIC research professor, and Gaëlle Lebreton, postdoctoral fellow in the same group, have published a study performed using Drosophila melanogaster in the Journal of Cell Science. This work reveals that in a multiple movement, a single cell can act as the leader and can drag the rest with it. The scientists have studied the tracheal development of Drosophila in vivo and describe the morphological characteristics of the leading cell and provide molecular details about how it drives the movement.

“Cancer researchers are keen to know how cells are organized to achieve migration and to form new capillaries to feed an expanding cancerous tumor,” explains Gaëlle Lebreton, first author of the article. “Our study gives new data about how angiogenesis might arise,” comments the French scientist at IRB Barcelona. Angiogenesis or the formation of new blood vessels is a critical process in the context of cancer because it is one of the steps that mark the transformation of a benign tumour into a malignant one. The formation of new blood vessels involves the synchronized movements of groups of cells. In this regard, understanding how these groups work will open up new research lines on angiogenesis.

Over seven hours, the scientists tracked a group of seven cells that form one of the tracheal branches of the fly Drosophila melanogaster in its first hours of development. The leading cell is the only one that has receptors for the growth factor FGF. The FGF signal stimulates a cascade of reactions in this cell in order to generate sufficient energy and to turn it into the promoter of motility.

“This is a novel piece of work because we monitored the entire process in vivo and because it is the first time we have seen, in an experimental context, that a single cell can lead this multiple migration,” says Casanova.

It is important to note that the development of trachea in the Drosophila fly is similar to that of bronchia in humans. Consequently, this development is also of biomedical interest in order to unravel the basic processes involved in the formation of new tissue.

Reference article:

Specification of leading and trailing cell features during collective migration in the Drosophila trachea
Lebreton G, Casanova J.
J Cell Sci. 2013 Nov 8. [Epub ahead of print]

 
 
This article was first published on the 20th of November 2013 in the news section of the IRBBarcelona website.
 
 

(2 votes)

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Here is our monthly round-up of some of the interesting content that we spotted around the internet:

News

– Developmental biologist Jim Smith, director of MRC National Institute for Medical Research, has been announced as the new MRC Deputy Chief Executive and Chief of Strategy.

– Elena Cattaneo is the winner of 2013 Stem Cell Person of the Year Award run by the Knoepfler lab stem cell blog. f you are interested in Elena’s work, you can read a Node post about one of her papers.

– If you are a member of the Society for Developmental Biology, nominations are now open for the 2014 SDB awards.

– And the shortlist for the 2013 Royal Society Winton Prize for Science Books has been announced. You can read the review of one of the shortlisted books, ‘Cells to Civilizations’, on this Node post.

Weird & Wonderful

– Halloween is the season for pumpkin carving, and twitter was full of science-themed pumpkins! We even carved our own Node Halloween pumpkin! And if you use stats in your research, you might also like this Halloween statistics cartoon.

– We spotted some stunning science cakes as part of a CRUK initiative, including this amazing cake representing a scientist hard at work in the lab.

– And if you were ever frustrated by how scientists in movies never seem to be able to pipette correctly, then this website is for you (scroll to the bottom for some of the best picks).

Beautiful and interesting images

– The winners of the Nikon Small World 2013 competition have been announced. Check out their website to see the stunning winning images!

– Ever wondered what a banana flower looks like in an MRI? Check this website for the answer– very beautiful!

– And check out this great trick of mimicry in nature!

Videos worth watching

– The finalists of the 2013 Dance your PhD competition have been announced. You can vote for your favourite dance here.

– This year marks the 100 years of the death of Alfred Wallace, and the New York Times released this nice animation of his life and legacy:
 

As usual, you can keep up with this and other content, including all Node posts and deadlines of coming meetings, by following the Node on Twitter.

(3 votes)

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Here are the highlights from the new issue of Development:

Broken-hearted over Hippo

Mammalian cardiac regeneration is greatly impeded by the massive loss of cardiomyocytes that occurs following acute injury. The failure of the remaining cells to proliferate is a considerable challenge for the field, but the molecular mechanisms that control cardiomyocyte proliferation in the adult heart are largely unknown. Now, on p. 4683, James Martin and colleagues demonstrate a role for Hippo signalling in suppressing adult and postnatal murine cardiomyocyte proliferation. Using conditional knockouts, the authors show that removal of Hippo pathway members Salv or Lats1 and Lats2 from normal adult cardiomyocytes results in increased proliferation, as these cells are able to re-enter the cell cycle and undergo cytokinesis. Moreover, removal of Salv from cardiomyocytes in vivo results in improved cardiac regeneration after adult myocardial infarction, a time when regeneration is usually severely impaired. Here, the authors observed reduced scarring and full restoration of cardiac function. This elegant study suggests that Hippo signalling is a repressor of adult cardiomyocyte renewal and regeneration.

Osr2 PAX a punch in palate formation

Precise orchestration of palate formation involves the complex interaction of signalling cascades and transcriptional networks in the developing craniofacial region. Pax9 and Osr2 have previously been implicated in palate formation, but little is known about how these molecular components interact within the greater regulatory network. Now, on p. 4709, Rulang Jiang and colleagues report a crucial role for Pax9 in patterning the anterior-posterior axis as well as outgrowth of the developing palatal shelves. The authors show that Pax9 regulates mesenchyme-epithelium interactions during pattern formation and that the expression of several key genes involved in palate development, such as Shh, Bmp4, Fgf10, Msx1 and Osr2, is reduced in Pax9 mutant mice. Interestingly, expression of Osr2 from the Pax9 locus was able to rescue the posterior, but not anterior, palate formation defect in the absence of Pax9 function. These data place Pax9 upstream of transcription factor Osr2 and signalling molecules Bmp4, Fgf10 and Shh in the molecular network that regulates palate development.

Par3 makes contact in migrating mesenchyme

Contact inhibition of locomotion (CIL) is a fundamental regulatory mechanism that ensures correct cell movement and migration. During CIL, cells form transient contacts but the molecular nature of such contacts is unknown. In this issue, Roberto Mayor and colleagues (p. 4763) investigate the role of the cell polarity protein Par3 in microtubule collapse and reorganisation during CIL in migrating neural crest cells. Using antisense morpholinos to Par3 in Xenopus and zebrafish, the authors show that loss of Par3 has a dramatic effect on migration and is essential for CIL both in vitro and in vivo. Par3 knockdowns fail to exhibit microtubule collapse at the cell-cell contact; however, this can be rescued by injection of an antisense morpholino to Trio, implicating the Rac-GEF Trio in migrating neural crest CIL. The authors propose a model in which CIL requires the local destabilisation of microtubules at the cell-cell contacts, which is controlled in a Par3/Trio-dependent manner.

Designer flies: accelerated genome editing in Drosophila

The immense power of Drosophila genetics has allowed invaluable insight into developmental biology. Despite these advances, a significant limitation has always been the lack of an efficient method for modifying select genetic loci. Now, on p. 4818, Jean-Paul Vincent and colleagues report high-efficiency homologous recombination in Drosophila with a novel gene-targeting vector. This can be achieved via a two-generation crossing scheme or via direct embryo injection. Importantly, both approaches yield few false-positives due to efficient negative selection, while readily detectable markers aid in the rapid identification of correctly targeted flies. The efficiency can be further increased by co-injecting the sequence-specific endonuclease CRISPR/Cas9. The investigators also report a series of vectors that can be used to insert different genetic elements into the targeted loci, such as mutated or tagged cDNAs and additional reporter genes. Their approach will enable genetic modification in a wide range of contexts, including in postmitotic cells. These tools will be a valuable resource for the Drosophila community.

Puffyeye regulates Myc-mediated cell growth

Proper control of cell size is vital to ensure the correct growth and development of any organism. The Myc family of proteins are key regulators of growth, but the mechanisms that control Myc protein levels are complex. Now, on p. 4776, Robert Eisenman and colleagues identify Drosophila Puffyeye (Puf), an orthologue of mammalian USP34, as a novel ubiquitin-specific protease (USP) regulating dMyc-dependant cell growth at the post-translational level. Using genetic interaction experiments, the authors demonstrate that puf opposes the activity of the ubiquitin ligase archipelago (ago) and that Puf acts to stabilise dMyc protein levels. Overexpression of puf in the eye and wing phenocopies dMyc overexpression, while expression of a catalytically inactive form of Puf had no effect, demonstrating the requirement of the Puf USP catalytic domain. Interestingly, the authors demonstrated that Puf can also regulate Ago and Cyclin E protein levels. These data reveal a new mechanism by which dMyc levels can be regulated by USPs in order to fine-tune cell growth.

GDF5 determines dendrite growth

Dendrite complexity determines the functional properties of neurons and the overall connectivity of neuronal circuits. The bone morphogenetic protein (BMP) family is known to regulate a myriad of developmental processes, but the extent to which different members of the family are involved in dendrite growth remains unclear. In this issue (p. 4751), Alun Davies and colleagues identify growth differentiation factor 5 (GDF5), a member of the BMP family, as a key regulator of dendrite growth and complexity in the pyramidal neurons of the developing hippocampus. Mice harbouring a mutation in Gdf5 showed dramatically reduced dendrite size and complexity. In vitro, exogenous GDF5 treatment was sufficient to increase elongation of the dendrites, but not the axons, of pyramidal cells derived from the developing mouse hippocampus. The authors further demonstrated that GDF5-mediated dendrite growth acts via the Smad signalling pathway and that GDF5-regulated HES5 expression is both necessary and sufficient for enhanced dendritic growth and complexity.

PLUS…

Nutritional regulation of stem and progenitor cells in Drosophila

Stem cells and their progenitors are maintained within a microenvironment, termed the niche, but it is known that systemic signals originating outside the niche also affect stem cell and progenitor behavior. Here, Utpal Banerjee and colleagues review recent studies of nutritional effects on stem and progenitor cell maintenance and proliferation in Drosophila. See the Review article on p. 4647

Cell-intrinsic drivers of dendrite morphogenesis

The proper formation and morphogenesis of dendrites is fundamental to the establishment of neural circuits in the brain. In this issue, Sidharth Puram and Azad Bonni review cell-intrinsic drivers of dendrite patterning and discuss how the characterization of such regulators advances our understanding of normal brain development and pathogenesis of diverse cognitive disorders. See the Review on p. 4657

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