The University of Maine Darling Marine Center will once again host a Developmental Biology Teaching Workshop, June 25-29, 2013.  Openings are still available!

This workshop is geared toward university faculty, postdocs, and graduate students interested in teaching developmental biology.  It provides basic hands-on experience with organisms commonly studied in teaching laboratories. These include sea urchins and sand dollars, planaria, Drosophila, chick embryos, Spirostomum, Hydra, Lumbriculus, and flowering plants. Techniques will range from classical microsurgical techniques to fluorescence microscopy and applications of reporter gene technology.

Course Instructors:
Dr. Leland Johnson, Augustana College, SD
Dr. Eric Cole, St. Olaf College, MN
Guest Instructor, Dr. Mark Spiro, Bucknell University, PA

This workshop is the recipient of a Non-SDB Educational Activities Grant from the Society for Developmental Biology.  For more information visit the course website here: http://www.dmc.maine.edu/workshops.html#devbiocourse

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Dear readers of the Node,

Hi there! My name is Caroline and I am the new Reviews Editor covering all things stem cells at Development. I come to you from the land down under, namely Australia, where I did my PhD on kidney development and stem cells in the lab of Prof Melissa Little at the University of Queensland. Shortly thereafter, I landed myself what I considered to be “the dream postdoc” studying lineage reprogramming and iPSC disease modelling in the lab of Prof Ihor Lemischka at Mount Sinai School of Medicine, New York. USA. But fate was not finished with me yet, and now I find myself in Cambridge, UK, in the hallowed halls of the Development offices. Having moved continents three times in less than two years, I am definitely ready to settle!

I am really looking forward to bringing you the latest and greatest in all things stem cells and development. The stem cell field grows larger by the month but no matter how big it gets, its foundations will always be in development.  The two are inextricably linked. In one sense, the stem cell field can be thought of as applied developmental biology, and this is certainly the case for stem cell therapies. But understanding the fundamental mechanism of how stem cells can give rise to an entire tissue or organism is as much an integral part of developmental biology as any other, and so deserves to be studied in its own right.

I can’t wait to hear more from everyone as my time here goes on. I’m really looking forward to meeting you at all at various conferences and getting your thoughts on stem cells in development! There are big things planned for stem cells in the journal this year so stay tuned!

(8 votes)

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When your model organism of choice is medaka, and you spend your mornings trying to rid your embryos of their tough chorion, you comfort yourself thinking that one day all the hard work will result in A) a paper, and/or, B) a visit to Japan. After all, medaka are Japanese killifish (Oryzias latipes). When the day in which one of these two options unexpectedly becomes true, you realise that medaka is truly the best model organism anybody could work on!

And so it was that a few weeks ago, I got an email from the RIKEN Centre for Developmental Biology in Kobe telling me I had a full travel grant to attend their 2013 Symposium, entitled “The Making of a Vertebrate”, and which would take place in March. The list of speakers was impressive, and the theme selected for this year’s meeting was particularly exciting. Our lab here in Seville works on vertebrate morphogenesis (Juan Martínez-Morales’ lab, at the Andalusian Centre for Developmental Biology) and the Symposium felt like the ideal place to tell our medaka-themed story.

At breakfast on the first day of the Symposium I met the other four lucky people who had also been awarded travel grants. We all came from different corners of the world, and none of us were working in our own countries. We bonded through our nomadic dispositions that morning, visiting each other’s posters in the afternoon, and by the time the sushi was served during the reception dinner that evening, we were plotting the conquest of Kobe.

The Symposium itself had a great start. The first session took on the origins of vertebrates, with a comprehensive overview by Nicholas Holland, asking what the true shape of the “tree of animal life” is.  His introduction was followed by talks on the hourglass model (Naoki Irie) and the evolution of chordates (Billie Swalla), both of which shed light on the question initially proposed by Dr. Holland. Next were the talks on hemichordates, annelids and the ancestry of vertebrates and their body plan. Detlev Arendt showed there is a conserved set of transcription factors, expressed in a specific, serial pattern in cnidarian gastric pouches, coelomic cavities in amphioxus, as well as in annelid mesodermal segments; suggesting that segmentation evolved before the split between cnidarians and bilateria. The final session of the day addressed the origins of pluripotency in vertebrates and its associated transcription factor network, which contains functionally overlapping genes that provide robustness to the network (Hitoshi Niwa) but has also evolved by gene co-option and duplication (Miguel Manzanares). The speakers were all engaging, the discussions insightful, and the organization of the whole day was great, including the best conference food I have ever tasted, which was also beautiful to look at: bento boxes.

Day two began with a fresh look on gastrulation, and I particularly enjoyed Masahiko Hibi’s images showing the timing of dorsal determinant transportation in the zebrafish yolk, and Hidehiko Inomata’s talk explaining how dorsoventral patterning is adjusted to the size of the embryonic axis. The afternoon’s subject was the Genetic Control of Morphogenesis, and included a talk on medaka (Hiroyuki Takeda), so that made it particularly thrilling for me. Dr. Takeda  is using a genome-wide approach to study epigenetic marks on key developmental genes, and finds their DNA-methylation status, as well as their histone modification states, change dramatically in time; suggesting that gene regulation occurs in “steps”.

The last day of the Symposium was all about vertebrate characters and their origins. It began, to my delight, with talk of dinosaurs and beautiful pictures of in situs on penguin embryos, with a compelling argument for the use of chick embryos as models for dinosaur morphogenesis (Koji Tamura). David Kingsley uses sticklebacks to address evolutionary changes, and suggested that evolution has few ways to achieve change, but uses them repeatedly: regulatory mutations, unlike deleterious loss-of-function ones, can be both advantageous and dramatic. The talk by Shigeru Kuratani discussed his lab’s work to clarify the patterning of craniofacial structures. They have successfully bred hagfish and have studied their embryology in minute detail, concluding that there is a “pan-cyclostome embryonic pattern” which is the ancestral programme of craniofacial development of vertebrates, and during evolution gnathostomes have lost or modified components of this pattern. I have mentioned my personal highlights, but would like to state that in general, the speakers were fantastic and it was hard to select only a few for this piece.

After the meeting was over, I made a short trip to Kyoto to see the sights. I am sharing some of the pictures I took during my visit, hoping that those of you who haven’t experienced Japan yet can have a peek at how magical it is. I hope you enjoy them.

Thank you very much indeed (domo arigato gozaimasu) to RIKEN CDB for the travel grant, and for an excellent and memorable meeting.

Finally, now that option B on my list became true, I better get on with making option A (the paper) happen too…our dear medaka are certainly doing their part!

Images: Fushimi-Inari Shrine, Chion-In Temple, Kinkaku-ji Temple, lunch at a market

(13 votes)

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Post-doctoral and PhD positions are available in the lab of Savraj Grewal, University of Calgary, Canada.

(https://www.facebook.com/The.Grewal.Lab).

The main focus of the lab is to study the control of growth using Drosophila as a model system. We use a combination of molecular, genetic and proteomic approaches to investigate the cell-cell signalling pathways and the genetic mechanisms that control how cell, tissue and body growth are regulated during development.

Post-doc applicants with a strong background in developmental biology, genetics, or molecular biology are encouraged to apply. PhD applicants should have a strong undergraduate degree in any area related to the biological sciences. Interested individuals should send a CV, a one-page statement of research interests, and three names of references to grewalss[at]ucalgary.ca. Applications will be accepted on an ongoing basis and positions will remain open until filled.

For more details about our lab, our research and the University of Calgary, please visit our lab web page:

https://www.facebook.com/The.Grewal.Lab

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This week we’re launching CiteAb – a brand new antibody search engine suitable for Developmental Biologists working with model organisms, including C. elegans, Drosophila, Zebrafish, Xenopus and Chick, as well as mammals. We feature nearly 1 million antibodies, rated by citations.

See http://citeab.com for more details.

This is a new site so we would very much welcome feedback from users of the Node.

Thanks :)

(3 votes)

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Over the last few weeks, you’ve been submitting your images for the Node and Development‘s stem cell cover competition. We received a large number of entries, and you’ve proved to us that stem cells – both in their natural environments and in a dish – can be just as beautiful as the embryos that normally grace our covers. After quite some deliberation, we’ve narrowed down the submissions to a short-list of five.

Now it’s your turn to vote for your favourite. The winning image will appear on a cover of Development, and will also feature on the new stem cell pages we’re developing for the journal’s website.

The poll will close at noon GMT on April 10th.

Here are the Final Five. Click on the image to see a larger version.

1. Immunofluorescence of the corn snake (Panterophis guttatus) dental organ with multiple generations of tooth germs. Sox2 expression (red) indicates putative dental stem cells in the epithelial lamina. DNA is stained with Hoechst (blue).

2. Fractal image of neural rosettes forming after the differentiation of mouse embryonic stem cells to neural stem cells. Cells are stained for Nestin (green) and PSA-NCAM (red).

3. Induced pluripotent stem cell colony surrounded by non-reprogrammed and feeder cells. Mouse embryonic fibroblasts were infected with viruses encoding transcription factors Oct4, Sox2 and Klf4 to reprogram them to pluripotency. A day 14 reprogramming culture was stained for E-CADHERIN (green), NANOG (red) and EZH2 (magenta). Dapi is shown in blue. This procedure can also be applied to human cells. The discovery of somatic cell nuclear reprogramming to pluripotency was awarded the 2012 Nobel Prize for Physiology or Medicine.

4. A rendered image of a primary neuronal stem cell culture in which cells were labeled with different fluorescently labeled proteins that differentiate between stem cells (orange/yellow) and their neuronal ‘offspring’ (blue/ green/ purple).

5. Confocal image of an adult mouse hippocampus, the area of the brain where new memories are formed. Astrocytes (green) were observed around the granule cell layer of the dentate gyrus, as indicated by cell nuclei (red). Some astrocytes were derived from neural precursor cell population (blue).

(10 votes)

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 The Revive Postdoc program offers up to 3 years fellowships to young scientists in stem cell research.

(1 votes)

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The 8th European Zebrafish Meeting, 9-13 July, Barcelona welcomes proposals from all areas of zebrafish research for consideration for oral and poster presentation.

This meeting will gather together researchers from all over the world to discuss the recent discoveries in the zebrafish field. All communications will be presented either as oral or poster presentations.

Don´t leave your submission for the last minute. We are pleased to remind you that the deadline for abstract submission is March 24, 2013.

(more…)

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Here are the highlights from the current issue of Development:

Mammary gland RankL-ed into making milk

Extensive remodelling of the mammary gland during pregnancy generates milk-producing lobuloalveolar structures. During remodelling, multipotent stem cells proliferate and differentiate into lineage-committed progenitor cells, which subsequently differentiate into mature epithelial cell types. It has been proposed that progesterone drives mammary stem cell expansion during pregnancy via paracrine signalling from progesterone receptor-positive sensor cells. On p. 1397, Christopher Ormandy and colleagues investigate how the resulting cells are directed towards the secretory lineage. Progesterone induces the expression of the transcription factor Elf5 in mouse mammary progenitor cells, they report, and Elf5 (which is essential for progenitor cell differentiation) cooperates with progesterone to promote alveolar development. They show that the progesterone receptor and Elf5 are expressed in different cell types, and identify the transcriptional activator RankL as the paracrine mediator of progesterone’s effects on Elf5 expression in progenitor cells and their consequent differentiation. RankL also mediates the progesterone-induced division of mammary stem cells. Together, these findings reveal how steroid hormones drive mammary gland remodelling during pregnancy.

Epidermal stem cell heterogeneity

Stochastic fluctuations in gene expression (transcriptional noise), which drive transitions between states, and complex regulatory networks, which define stable interconvertible ‘attractor’ states, are both thought to be involved in the control of stem cell fate. Because population-based studies lack the resolution to reveal the heterogeneity resulting from different attractor states or to uncover their functional significance, on p. 1433 Fiona Watt and colleagues use single-cell gene expression profiling to investigate heterogeneity among human epidermal stem cells. Markers for these cells include the Notch ligand delta-like 1 (DLL1) and the EGFR antagonist LRIG1, but the expression of these proteins is known to vary between cells. The researchers now show that DLL1 expression discriminates between two populations of undifferentiated basal keratinocytes that differ in adhesion and proliferation, and that have distinct transcriptional profiles. These results indicate that intercellular differences in gene expression among human epidermal stem cells cannot be attributed solely to random stochastic fluctuations and suggest that this heterogeneity affects the interaction of these cells with their environment.

Adipocytes and wound healing

Acute wound healing, which restores the essential barrier function of the skin, requires the coordination of the proliferation and migration of both keratinocytes and fibroblasts for epidermal and dermal repair, respectively. Skin healing is known to involve communication between haematopoietic cells, keratinocytes and fibroblasts, but could it involve other intradermal cell types? Barbara Schmidt and Valerie Horsley (p. 1517) have been investigating the involvement of intradermal adipocytes in skin wound healing in mice. They report that immature adipocytes are activated during the proliferative phase of acute skin wound healing and that mature adipocytes appear in healing wounds concurrently with fibroblasts. Moreover, by studying wound healing in mice with genetic defects in adipogenesis and in mice treated with pharmacological inhibitors of adipogenesis, they provide evidence that suggests that adipocytes are necessary for fibroblast recruitment and for dermal reconstruction. Further experiments are now needed to elucidate how adipocytes mediate fibroblast function during the healing of acute skin wounds and to determine whether they also aid the healing of chronic wounds.

Blood vessels guide heart innervation

Peripheral nerves and blood vessels lie close together and have similar branching patterns in many tissues, which suggests that their development might be coordinated. Previously, Yoh-suke Mukouyama and co-workers reported that signals secreted by sensory nerves determine vascular patterning in the skin. Here (p. 1475), the researchers show that there is an anatomical congruence between sympathetic nerves and coronary veins in the developing mouse heart. In contrast to the situation in skin, this neurovascular association is not important for vascular patterning, but is instead required for the functional sympathetic innervation of the heart. Vascular smooth muscle cells (VSMCs) associate with coronary veins during angiogenic remodelling, they report, and mediate the extension of sympathetic axons within the subepicardium by secreting nerve growth factor (NGF). Subsequently, venous VSMCs downregulate NGF expression and arterial VSMCs begin to secrete NGF, which stimulates the axons to innervate coronary arteries in the myocardium. Thus, sequential expression of NGF in subepicardial venous VSMCs and myocardial arterial VSMCs determines the heart’s stereotypical pattern of sympathetic innervation.

Timely BMP patterns neural tube

In many embryonic tissues, graded signals (morphogens) provide the positional information that governs the pattern of cellular differentiation. It is widely thought that cells interpret morphogen gradients by producing corresponding levels of intracellular signalling activity, which regulate differential gene expression. But could other, distinct, mechanisms be used to interpret some morphogens? On p. 1467, James Briscoe and co-workers investigate the morphogen activity of bone morphogenetic protein (BMP) signalling in the chick dorsal neural tube. BMPs are thought to provide the positional information that specifies the spatial pattern of the dorsal interneurons. In neural tube explants, the researchers report, the duration of exposure to Bmp4 generates distinct levels of intracellular signalling and induces specific dorsal identities. Moreover, they find that a dynamic gradient of BMP activity progressively specifies more dorsal identities in the neural tube in vivo. Given these results, the researchers propose a model for morphogen interpretation in which the temporally dynamic control of signalling is required to specify the spatial pattern of cellular differentiation.

Grandmother, what big teeth you have!

Although many organs renew throughout life, the regenerative capacity of some organs varies between species. For example, reptiles replace their teeth continuously, whereas mammals have only a single round of tooth replacement. The development of new teeth involves dental epithelial cells that are competent for tooth formation. Now, Irma Thesleff and colleagues (p. 1424) identify the transcription factor Sox2 as a marker for these cells. The researchers report that Sox2 is expressed in the dental lamina that gives rise to successional teeth in ferrets and humans, which have a single round of tooth replacement, and in five reptiles with continuous tooth replacement. Sox2 is also expressed in the dental lamina during the serial addition of mammalian molars and, in mice, Sox2⁺ cells in the first molar give rise to the sequentially developing second and third molars. These data suggest that Sox2 function has been conserved during evolution, and identify tooth replacement and the serial addition of primary teeth as variations of the same developmental process.

PLUS…

Crossing paths: cytokinin signalling and crosstalk

Cytokinins are a major class of plant hormones that are involved in various aspects of plant development. Recent studies, reviewed here by Helariutta and colleagues, have shown that cytokinins interact with a number of other plant hormones to regulate plant development.

See the Review article on p. 1373

Conserved non-coding elements and cis regulation: actions speak louder than words

The literature is strewn with examples of conserved non-coding elements being able to drive reporter expression, but the extent to which such sequences are actually used endogenously in vivo has been unclear. Here, Nelson and Wardle outline the various methods used to define cis-regulatory elements driving gene expression, and discuss the complex relationship between sequence conservation and the functional equivalence of such elements during development and across evolution.

See the Review article on p. 1385

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WELCOME to the INFORM PhD Program!

The INFORM program (INformation Flow and ORganization at the Membrane) sets up an interdisciplinary consortium at the site of Scientific Park of Luminy in Marseilles, gathering 12 laboratories in Biology, Mathematics and Physics. The objective is to quantitatively understand the biochemical and mechanical basis of cell signaling at different scales from molecular to cellular and tissue levels. The project will allow scientific progress in understanding the dynamics of signaling focusing on a quantitative description of biological mechanisms.

6 PhD fully funded positions will be available for Fall 2013 (aplication deadline May 10th 2013). This PhD program is highly interdisciplinary and based on collaborative projects between partners of the consortium. We encourage graduate students from different backgrounds to apply, biologists but also engineers, physicists and mathematicians.

More details about INFORM project research /technologies and PhD program application procedures can be found on our Website: labexinform.wordpress.com

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