Issues

Summary: This report highlights the major themes and advances presented at the recent EMBL conference 'Hematopoietic stem cells: from the embryo to the aging organism'.

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.

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.

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.

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.

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.

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.

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.

Summary: During zebrafish angiogenesis, endothelial PKA activity regulates the transition from sprouting to stabilisation of nascent vessels, preventing excessive tip cell formation and hypersprouting.

Summary: Although the Drosophila insulin gene is broadly expressed, its regulation is complex - with multiple cis-regulatory elements integrating nutritional and tissue-specific inputs.

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.

Summary: Changes in the expression domains of the spalt and cut transcription factors are associated with the acquisition of tracheal morphology innovations in insects.

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.

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.