IN THIS ISSUE
Summary: This review discusses the mechanisms that generate neuronal diversity in the spinal cord, highlighting how different developmental populations produce neurons with distinct somatosensory functions.
STEM CELLS AND REGENERATION
Control of germline stem cell differentiation by Polycomb and Trithorax group genes in the niche microenvironment
Highlighted Article: Loss of Polycomb group genes in Drosophila ovarian escort cells causes Trithorax-dependent activation of Dpp and consequently germline stem cell tumors.
Highlighted Article: Analysis of the expression pattern and targets of the human transcription factor LEUTX suggests a two-stage model for embryonic genome activation, also involving DRPX.
Summary: Adult medaka intestinal stem cells (ISCs) proliferate within a niche functionally equivalent to that in the mammal. Like mammalian ISCs, but unlike medaka retinal stem cells, their mode of division is largely symmetric.
Activation of Smad2 but not Smad3 is required to mediate TGF-β signaling during axolotl limb regeneration
Summary: TGFβ signaling has been implicated in scar formation after wounding. During axolotl limb regeneration, differential regulation of Smad effectors may explain why these animals do not scar.
Summary: Inhibiting fibroblast migration during regeneration in axolotl reveals the importance of fibroblasts for blastema-based limb regeneration but not non-blastemal skin regrowth.
Summary: In the fly wing, the transmembrane protein Crumbs antagonises Notch signalling. Crumbs, in turn, is inhibited by the WD40 domain protein Ebi, thus promoting Notch activity.
Highlighted Article: In the chick wing, the relative timing of the specification of antero-posterior positional values and self-organising mechanisms determines digit patterning and identity.
Vinculin b deficiency causes epicardial hyperplasia and coronary vessel disorganization in zebrafish
Summary: The focal adhesion protein vinculin is required in epicardium and endocardium; its depletion leads to dysregulated FAK signalling and a phenotype mimicking dilated cardiomyopathy.
Brg1 plays an essential role in development and homeostasis of the duodenum through regulation of Notch signaling
Summary: Brg1, a core subunit of the SWI/SNF chromatin remodeling complex, regulates morphogenesis, differentiation and cell survival of the duodenum, by modulating expression of Notch pathway ligands.
A novel small molecule that disrupts a key event during the oocyte-to-embryo transition in C. elegans
Summary: The small molecule C22 induces expression of the LET-607 transcription factor, leading to mis-regulation of protein trafficking and thus impairing eggshell formation and the oocyte-to-embryo transition.
Early formation of the Müllerian duct is regulated by sequential actions of BMP/Pax2 and FGF/Lim1 signaling
Summary: In the developing female reproductive tract, BMP/Pax2 and FGF/Lim1 axes operate in a spatio-temporally regulated manner to promote specification and invagination of Müllerian duct precursors.
Summary: The transcription factor Tbx3 is required for eye formation. Although neither Tbx3 nor Pax6 alone is sufficient, together they can determine retina from pluripotent cells in Xenopus.
Summary: In both mouse and Xenopus, Setd7 is a key regulator of the pancreatic differentiation program, modulating chromatin state at pancreatic regulatory regions in cooperation with Foxa2.
cAMP-dependent protein kinase A (PKA) regulates angiogenesis by modulating tip cell behavior in a Notch-independent manner
Summary: During zebrafish angiogenesis, endothelial PKA activity regulates the transition from sprouting to stabilisation of nascent vessels, preventing excessive tip cell formation and hypersprouting.
Complex cis-regulatory landscape of the insulin receptor gene underlies the broad expression of a central signaling regulator
Summary: Although the Drosophila insulin gene is broadly expressed, its regulation is complex - with multiple cis-regulatory elements integrating nutritional and tissue-specific inputs.
Microtubule-severing activity of the AAA+ ATPase Katanin is essential for female meiotic spindle assembly
Summary: In C. elegans, the MEI-2 subunit of Katanin is required for its microtubule-severing activity. Katanin variants that can bind but not sever microtubules can not support normal meiotic spindle assembly.
Genetic basis for the evolution of organ morphogenesis: the case of spalt and cut in the development of insect trachea
Summary: Changes in the expression domains of the spalt and cut transcription factors are associated with the acquisition of tracheal morphology innovations in insects.
The evolutionarily conserved transcription factor Sp1 controls appendage growth through Notch signaling
Summary: Analysis of the transcription factor Sp1 in the fly leg reveals its key role in regulating segmentation, acting at least in part through the Notch ligand Serrate.
TECHNIQUES AND RESOURCES
Summary: Multiplexed in situ hybridisation chain reaction allows visualisation of multiple mRNAs in a single sample with subcellular resolution. This technology can be applied in many species.