Here are the highlights from the current issue of Development:

In-cyst-ing on germ cell development

During gametogenesis in many organisms, germ cells undergo synchronous, incomplete divisions just before meiosis that generate interconnected cell groups known as cysts, but does a cyst stage always occur during mammalian gametogenesis? Here (p. 2075), by lineage marking the progeny of primordial germ cells (PGCs) in embryonic mouse gonads, Lei Lei and Allan Spradling show that mouse PGCs initially develop into cysts containing two, four or eight cells. In female gonads, these cysts fragment into smaller cysts that associate with the cysts of unrelated progenitors. Interestingly, the number of female cysts per PGC at the time of meiotic entry corresponds closely with the number of primordial follicles produced by each progenitor, which suggests that cyst fragmentation determines the number of oocytes and possibly also their quality. Male cyst cells also break apart, the researchers report, which amplifies the number of spermatogonial stem cells. Together, these results indicate that cyst formation and cyst fragmentation are fundamental stages in the development of male and female mouse gametes.

Meiotic progression, ETC

During mitosis, ubiquitylation of the anaphase inhibitor securin by the E3 ligase anaphase-promoting complex/cyclosome (APC/C) targets securin for proteolysis, which triggers sister chromatid separation. Securin is also implicated in meiotic progression. Thus, during both mitosis and meiosis, securin expression must be tightly regulated to enable its timely action. On p. 2149, Risa Kitagawa and co-workers investigate the mechanism underlying this regulation by analysing the subcellular localisation of the securin IFY-1 during C. elegans development. IFY-1 expression is high in the cytoplasm of germ cells, they report, but declines following meiosis I, and remains low during meiosis II and following mitoses. The researchers identify the HECT-E3 ligase ETC-1 as a regulator of the cytoplasmic levels of IFY-1 and CYB-1 (cyclin B1), and show that ETC-1 ubiquitylates IFY-1 and CYB-1 in vitro in the presence of the E2 enzyme UBC-18. These and other data suggest that a novel mechanism, mediated by ETC-1, cooperates with APC/C to regulate the timing of meiosis during germ cell development in C. elegans.

Tentacles illuminate appendage evolution

Evolution of the capacity to form appendages (secondary outgrowths from the principal embryonic axes) potentiated the diversification of animal body plans. The basic mechanisms that underlie appendage growth in bilaterian model systems have been identified but little is known about appendage development in pre-bilaterians. Now, on p. 2212, Matthew Gibson and colleagues report that three processes contribute to tentacle development in the sea anemone Nematostella vectensis. The initial step in tentacle development in this early-branching metazoan, they report, is the formation of a thickened ectodermal placode at the oral pole that progressively divides into four distinct tentacle domains, probably through the restricted expression of key effector genes. Next, Notch signalling triggers apicobasal thinning of the tentacular ectoderm, which drives the elongation of these primordia. Concomitantly, oriented cell rearrangements help to shape the elongating tentacles. By defining the mechanism of embryonic appendage development in an early-branching metazoan, these findings provide a foundation for understanding the evolutionary diversification of animal body plans.

Ephrin B1 sticks up for developing brain

The apical membrane of apical progenitors (APs) in the developing mammalian cortex is involved in cell-cell and cell-extracellular matrix (ECM) adhesion events that maintain the integrity of the developing neuroepithelium. Apical adhesion is important for several aspects of neural development but its regulation is poorly understood. Here (p. 2082), Alice Davy and colleagues investigate the function of ephrin B1, a cell-surface protein that activates cellular signalling on binding ephrin receptors (via reverse signalling), in the morphogenesis of the developing mouse cortex. The researchers report that some Efnb1-deficient embryos display exencephaly and exhibit morphological alterations of the neuroepithelium that suggest defects in neural tube closure. Ephrin B1 is required in APs to maintain apical adhesion, they report, and ephrin B1 reverse signalling controls integrin-based cell-ECM apical adhesion through inhibition of ADP-ribosylation factor 6. These results suggest that ephrin B1 maintains the apical adhesion of APs during cortical development, a function that is essential for neural tube morphogenesis.

Fascin-ating melanoblast migration

The actin-bundling protein fascin 1 is expressed at specific times and places during development, and is often expressed in tumours. Fascin 1 has a clear role in cell migration in vitro but what is its role in vivo? To answer this question, Laura Machesky and co-workers have been studying the role of fascin 1 in the mouse melanocyte lineage and in human melanoma cells (p. 2203). They report that fascin 1 knockout mice have hypopigmentation defects that arise from reduced melanoblast migration and proliferation during embryogenesis. By studying live embryo skin explants, they show that fascin 1-null melanoblasts migrate and differentiate in the skin but with a lower efficiency than wild-type melanoblasts. They also show that fascin 1 depletion slows melanoblast proliferation in vivo and human melanoma cell growth in vitro. The researchers suggest, therefore, that transient expression of fascin 1 in mouse melanoblasts during embryogenesis promotes their migration and proliferation, and that fascin 1 expression may aid the proliferation and invasion of some tumour cells.

Plant vascular tissue lines up

Plant vascular tissue is derived from the cambium and procambium, which are meristems that contain long thin stem cells that divide down their long axis. These highly organised divisions produce characteristic files of cells in the xylem and ensure spatial separation of the xylem and phloem. The ligand-receptor pair CLE41-PXY regulates vascular cell division, vascular organisation and xylem differentiation. Now, on p. 2224, Simon Turner and colleagues provide new insights into the factors that act downstream of PXY in Arabidopsis. The researchers show that WOX4, which encodes a transcription factor previously shown to act downstream of PXY, acts redundantly with WOX14 to regulate vascular cell division but that neither gene regulates vascular organisation. Moreover, they identify an interaction between PXY and the receptor kinase ERECTA that affects the organisation of the vascular tissue but not its rate of cell division. The researchers propose, therefore, that PXY and ERECTA signalling integrate cell division and vascular organisation in the Arabidopsis stem, thereby ensuring normal stem formation.

PLUS…

An intracellular partitioning-based framework for tissue cell polarity in plants and animals

Tissue cell polarity plays a major role in plant and animal development. Coen and colleagues propose that a fundamental building block for tissue cell polarity is the process of intracellular partitioning, which can establish individual cell polarity in the absence of asymmetric cues. See the Hypothesis article on p. 2061.

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I got the call and immediately said yes. What a thrill to be asked to join the best developmental biology journal there is! Then I talked to some colleagues afterwards and one said “but that’s a LOT of work!!”. Well yes, but it’s worth it. See, Development published my first paper as an independent PI, and it’s the journal that I have probably most read in my career. So I care deeply about it. Plus, being asked to join such an illustrious group of folks, themselves preceded by a pantheon of developmental biologists, how could I say no?

Aside from being honoured by the request, I see this as a mission of sorts. Developmental Biology, as a discipline, and Development as a journal, are vibrant and growing, and rapidly evolving. Indeed, just in the last few months, I’ve eagerly read at least a dozen of papers in Development that have excited and invigorated me. Other journals have recently published some groundbreaking developmental biology papers. The field is alive and strong, and this journal has one of the most important roles in bringing the most exciting discoveries in developmental biology to light.

My personal mission as editor is to bring some of the best and most exciting papers in developmental biology to this journal. My specialty is heart development and more recently stem cell biology and chromatin-based regulation, but I am excited about many aspects of development. The stem cell aspect to developmental biology is one that has recently become very fashionable and is indeed an important and emerging part of our field. In this regard, I am certainly keenly scoping out stem cell-related stories to bring to Development. But I am really mostly very much driven to bring the most interesting and illuminating developmental biology papers to our journal, and get them the broadest possible exposure. For this I need your best work submitted, and your best minds as reviewers! In return I will be keenly selective, but fair and rapid; all the hallmarks that you have come to expect from Development!

I look forward to the many papers I will see come across my desk, and to helping shepherd your best work in Development!

(8 votes)

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On the 25th and 26th of February 2013 we were invited to attend a joint UK-Japan workshop on Neural Epigenetics at the British Embassy in Tokyo, which aimed to stimulate collaboration between researchers from the two countries. The event was organised by Adrian Moore from the RIKEN Brain Science Institute, Tokyo, and Adrian Bird from the MRC Cell Biology Institute, Edinburgh. Speakers from the UK and Japan presented their work to an audience of scientists working in the field, which included young Japanese and UK based scientists, and in a further public session to a wider audience facilitated by simultaneous translation between Japanese and English. Attending the workshop was a great opportunity to hear some of the current ideas in epigenetics and to meet some of the researchers in a relaxed environment.
After the meeting we were funded by the British embassy to remain in Japan for a further 10 days to visit Japanese research centres, where we were hosted by Japanese researchers. We visited two of Japans famous RIKEN institutes on our trip, the Brain Science Institute in Tokyo and the Centre for Developmental Biology in Kobe. We were given a tour of their state-of-the-art facilities, where we met with investigators with a wide range of interests who were enthusiastic to discuss their work with us. We also spent some time with international postdocs and students who made us aware of the funding opportunities available for oversees scientists to work at RIKEN institutes. At Kyoto University we met with researchers and were privileged to be shown around the Centre for iPS Cell Research and Application. We also attended the International Student Seminar at Kyoto University where we met many Japanese and international students and heard about their research projects. Whilst in Kyoto we also visited the Medical Science and Brain Science Institutes at Doshisha University where we met with researchers and Phd students.
In addition to the scientific programme, we had a couple of days to explore the cities we visited in Japan. We visited some stunning temples and Zen gardens in Kyoto and experienced the bright lights of Tokyo at night-time. The trip was a fantastic opportunity for us to become familiar with Japan, both it’s scientific infrastructure and it’s rich culture, and we hope that programmes like this will continue to give the same opportunities to other young researchers interested in the working in Japan.

Robert Blassberg and Mina Gouti are postdocs in James Briscoe’s lab at MRC NIMR and Marcus Leiwe is a PhD student in Ian Thompson’s lab at MRC Centre for Developmental Neurobiology at King’s College London.

(4 votes)

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SpotOn, Nature Publishing Group’s online forum for science policy, outreach and tools, and organiser of community events, is currently running a series on the use of social media for science outreach. As part of this series, we were asked to share our experience of setting up and running the Node.

If you’re interested in hearing a bit more about the motivation behind setting up the Node, and our impressions on how the project is going, I’d encourage you to read the case study (written by Eva Amsen – the Node’s founding Community Manager, who has recently moved on to pastures new – and Katherine Brown – Development‘s Executive Editor). From our side, the invitation to write this piece provided us with a great opportunity to reflect on the original aims of the Node, and to try and assess the degree to which we’ve achieved those aims. I think we’re doing pretty well and I hope you’ll agree! Of course, the Node is really YOUR site, not ours, and if there’s one thing we’d like you to take away from the case study, that’s it: the Node exists because the community wanted it, and you’re free to post what you think the community would be interested in reading about.

As well as the Node post, I’d really encourage you to take a look at some of the other social media case studies on the SpotOn site – they’re all collected together here, and they cover a huge range of different projects. Some of the projects people have taken on (particularly those doing it in their spare time and with no budget) are pretty impressive, and a definite source of inspiration!

(3 votes)

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This week, Disease Models & Mechanisms (DMM) formally announced the appointment of a new team of academic editors to lead the journal. Ross Cagan, Associate Dean of the Graduate School for Biological Sciences at Mount Sinai Medical Center, succeeds Vivian Siegel as the Editor-in-Chief, and he is joined by Senior Editors Monica Justice, Professor of Molecular and Human Genetics at Baylor College of Medicine, and George Tidmarsh, Chief Executive Officer at La Jolla Pharmaceutical Company.

Ross, Monica and George describe their interest in and vision for DMM in an inaugural editorial published in the latest issue of the journal. “This is a challenging but also an exciting time for science”, they write. “Our tools are not only more powerful, their level of improvement itself is accelerating. Not surprisingly, we are now trying to imagine how these tools can be applied to disease. What we find remarkable is that the founders of DMM understood these trends years ago.”

Describing some of the obstacles to the translation of biological findings to clinical benefit, they continue: “Many of the failures we have seen in translating novel basic biological discoveries to useful medicines are a result of the inadequacies of the animal models we use at the critical juncture between bench and bedside”. To address these inadequacies and promote future drug development, the team aims to introduce new standards for the rigorous preclinical assessment of animal models of disease.

Another issue raised is the lack of reproducibility of scientific findings, which has been reported in several journals. The new editors argue that negative data can be as informative as positive data when exploring therapeutics, so aim to encourage the publication of useful negative results: “….we will help promote –through our publications – a change in the scientific culture responsible for the asymmetric publication of positive results”.

Vivian Siegel, Broad Institute of MIT and Harvard, has stepped down after four years as Editor-in-Chief. In her farewell editorial, she reflects on the changes that DMM has undergone since launch, including the move to become open-access and, recently, a change in Creative Commons license to further promote access and sharing.

“About a year and a half ago, I agreed to become the Director of Scientific Education and Public Communications at the Broad Institute of MIT and Harvard, and realized I would have limited time to devote to DMM, too little to give it what it needs to continue to grow” Vivian writes, explaining her decision to leave DMM. “I encouraged The Company of Biologists to identify academic editors instead of another professional editor to succeed me, as I felt that the journal had now reached an age where its lead editors should be researchers actively engaged in the work covered by the journal.”

DMM is an open-access biomedical journal that publishes research and reviews focusing on the use of model organisms to provide insight into disease mechanisms, diagnostics and therapeutics. Founded in 2008, the journal was the fourth to be launched by the Company of Biologists.

To find out more and access the latest issue of the journal, go to http://dmm.biologists.org/

(2 votes)

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Olivier Pourquie, Nipan Patel, Claudio Stern, John Wallingford, Mary Mullins, Alejandro Sanchez-Alvarado, Andrea Streit, among other will teach, hands-on, the paradigms, problems and technologies of modern Developmental Biology. The course will start with a plenary lecture by Scott Gilbert about the history and concepts in Developmental Biology.

The course will take place in the summer of the south hemisphere (5^th to 17^th January 2014), in the beautiful fishing village of Quintay, at the Centre for Marine Biological Research (CIMARQ, in Spanish).   The best Latin American students in this course will be selected, including a fellowship, to participate at the Embryology course in Woods Hole.

The course is intended for Latin American and non-Latin American applicants. We believe that the interaction between the students will establish links and promote a culture of international collaboration that will further contribute to the field.

Fellowships will be available

DEADLINE 31^st July 2013

More information about the course in:

http://biodesarrollo.unab.cl/

For a summary about the previous course see:

https://thenode.biologists.com/a-wave-from-quintay-2/

(5 votes)

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The Center for Molecular Medicine Cologne (CMMC) is a multidisciplinary center at the University of Cologne providing a forum that brings together physician scientists with basic researchers from the Faculty of Medicine and the Faculty of Mathematics and Natural Sciences to perform competitive basic, disease-oriented research. The mission of the CMMC is to advance the understanding of the underlying molecular and cellular mechanisms as a prelude to improving prevention, diagnosis and treatment of many common health problems. For further information, please visit http://www.zmmk.uni-koeln.de.

The Center for Molecular Medicine Cologne invites applications of bright and motivated individuals for the Junior Research Group “Developmental Genomics” of Dr. Alvaro Rada-Iglesias.

One full time Post-doctoral fellow

The position is immediately available for 24 months with the possibility of extension. The position is based on the German TV-L salary conditions. The CMMC places strong emphasis on gender equality and seeks to increase the proportional representation of women in this field. Applications from female scientists are especially welcomed; suitably qualified women will be given preferential consideration unless other candidates clearly demonstrate superior qualifications. We also welcome applications from disabled candidates, who will also be given preferential consideration over applicants with comparable qualifications.

What we look for:
The ideal candidate should hold a PhD and demonstrated research experience in developmental biology, preferentially in one or more of the common vertebrate model organisms (mouse, chicken, frog or zebrafish). Experience with routine molecular biology techniques is also required. In addition, candidates with previous experience in stem cell or chromatin biology are also encouraged to apply. We look for highly motivated candidates willing to expand their previous expertise and interests as part of a multidisciplinary and collaborative scientific environment. The successful candidate will receive mentoring and will be given the opportunity to develop his/her own projects in preparation for a future independent career.

Research overview:
During mammalian embryogenesis, cell fates are acquired according to highly defined spatiotemporal patterns, which involves the deployment of cell type specific gene expression patterns as developmental programs unroll. Focusing on the crosstalk between transcription factors and epigenetics, our group aims to better understand the transcriptional regulatory principles that orchestrate the earliest steps of mammalian development. In doing so, our ultimate goal is to characterize the vast non-coding genomic space of the human genome and to investigate how genetic variation within non-coding regulatory elements can contribute to common and congenital human diseases.

In order to gain a global as well as mechanistic understanding of these biological processes, our lab uses a multidisciplinary approach where in vitro (i.e. human and mouse embryonic stem cells) and in vivo developmental models are combined with biochemical and genomic approaches. Please visit http://zmmk-ari.uni-koeln.de/Home.html to learn more about our previous work and interests.

Research environment:
CMMC along with its partner institutes such as the Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, Cologne Center for Genomics and Max Planck Institute for Biology of Ageing research all located in a same campus provides a vibrant scientific community. Therefore, the CMMC`s JRG in “Developmental Genomics” is placed perfectly at an environment where the basic research meets its cutting edge of translational science.

If you have further questions please do not hesitate to contact Dr. Alvaro Rada-Iglesias: aradaigl@uni-koeln.de

Please forward your complete application including CV, a brief statement of scientific interests and three reference letters (in a single pdf document) until 31.05.2013 by e-mail, quoting the reference number e129 to Dr. Alvaro Rada-Iglesias: aradaigl@uni-koeln.de and in CC. to Dr. Debora Grosskopf-Kroiher (Managing Director, Center for Molecular Medicine Cologne) (zmmk-office@uni-koeln.de).

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Last week, I was distracted somewhat by a palaeontology article in Nature: Reisz and colleagues reported their discovery of some fossilised dinosaur embryos. Not exactly relevant to my research, but very cool nonetheless…

The remains that they unearthed in southern China are from the early Jurassic period, almost 200 million years old, and are thought to belong to a Lufengosaurus species. This was a sauropodomorph dinosaur: a group distinguished by their large size, with a very long neck and tail and a small head. The most famous of the sauropodomorphs were probably the Diplodocus species.

These fossils are so unusual, and so informative, because they include embryos at a range of developmental stages. The majority of fossilised dinosaur embryos discovered to date have been single clutches of eggs, all synchronised in their development, which provides only a snapshot of development in that particular species. Finding a whole collection of samples from the same species, but at different stages, gives a rare insight into the dynamics of development in an extinct animal.

The authors focused on the growth of the thigh bone, analysing 24 femurs that ranged in length from 12 to 22 mm. Using sectioning and histological techniques, they showed that these bones were highly vascularised at all stages, so they think that these giant dinosaurs began life with rapid embryonic growth.

They also observed that the dinosaur femurs became thicker on one side as they grew larger, and developed a prominent fourth trochanter (an outgrowth to which the main thigh muscle attaches). In living tetrapods, asymmetrical bone thickening and the growth of skeletal features at muscle attachment sites depends on the muscles being active during embryonic development. This suggests that these ancient embryos also used their muscles to move around inside their eggs, and that these movements were an important part of their development too.

I was really amazed by how much information could be gleaned from these tiny fossilised remains. Geology rocks! In evo-devo, we use observations from extant species to make inferences about their common ancestors, but if palaeontology can provide insights into the embryonic development of extinct animals, it might help us to think about the evolution of some developmental processes from a different, and very interesting perspective.

Reisz, R.R. et al (2013) Embryology of Early Jurassic dinosaur from China with evidence of preserved organic remains, Nature 496: 210-214.

(4 votes)

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A couple of days ago, the University of Chicago Development, regeneration and stem cell journal club posted their first piece on the Node – a write-up of the discussion they’d had in their recent journal club meeting. It’s a great summary and analysis of a recent Development paper and its context within the field, and I’d encourage you to read it!

This piece marks the first in what we hope will be an irregular series of journal club reports from the Chicago group, and we’d like to find other developmental biology or stem cell journal clubs out there interested in writing for the Node. After all the effort of reading, analysing and discussing a paper for a journal club, we’d like to give you the opportunity of sharing that discussion with a wider community, and not just with your immediate colleagues.

If you’re interested in contributing to this, please get in touch at thenode[at]biologists.com. We’d love to hear from you!

(10 votes)

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