Table of Contents
IN THIS ISSUE
- Measuring forces and stresses in situ in living tissues
Summary: This Primer summarizes the current range of invasive and non-invasive techniques to measure forces in cells and tissues, and discusses their applications in developmental contexts.
- The formation and function of the cardiac conduction system
Summary: This Review discusses the complex gene regulatory networks that act in stage-, tissue- and dose-dependent manners to control the development of the cardiac conduction system.
STEM CELLS AND REGENERATION
- Genetic analysis of Runx2 function during intramembranous ossification
Summary: Runx2 is essential for the osteoblastic differentiation of Prx1- and Sca1-expressing mesenchymal stem cells during intramembranous ossification in mice.
- Genes implicated in stem cell identity and temporal programme are directly targeted by Notch in neuroblast tumours
Summary: Genome-wide screens identify direct targets of Notch involved in promoting neural stem cell tumours in Drosophila, tying Notch into the transcription factor network coordinating these stem cells.
- Single epicardial cell transcriptome sequencing identifies Caveolin 1 as an essential factor in zebrafish heart regeneration
Highlighted article: Gene expression analyses reveal that zebrafish epicardial cells are heterogeneous and identify many new epicardial markers, including Caveolin 1, which is shown to be essential for heart regeneration.
- The zebrafish tailbud contains two independent populations of midline progenitor cells that maintain long-term germ layer plasticity and differentiate in response to local signaling cues
Summary: Progenitor cells that generate the midline tissues of the zebrafish floor plate, notochord, and hypochord make germ layer decisions after gastrulation based on local canonical Wnt and Notch signaling.
- The transcriptional repressor Blimp-1 acts downstream of BMP signaling to generate primordial germ cells in the cricket Gryllus bimaculatus
Highlighted article: Blimp-1, a master regulator of PGC formation in mice, acts downstream of BMPs to generate PGCs in the cricket, highlighting that germ cell specification mechanisms are conserved between mice and crickets.
- Sonic hedgehog controls enteric nervous system development by patterning the extracellular matrix
Highlighted article: Gut epithelium-derived sonic hedgehog acts indirectly on the developing chick enteric nervous system by regulating the composition of the intestinal microenvironment.
- RING1 proteins contribute to early proximal-distal specification of the forelimb bud by restricting Meis2 expression
Highlighted article: RING1 proteins, which are essential components of Polycomb repressive complex-1, control proximal-distal patterning of the mouse forelimb by integrating developmental signals to regulate MEIS expression.
- Neurogenesis in sea urchin embryos and the diversity of deuterostome neurogenic mechanisms
Summary: The process of neurogenesis in sea urchins shares features with chordate neurogenesis but is distinct from that seen in other ambulacraria, highlighting that deuterostomes employ diverse neurogenic mechanisms.
- Neurogenic gene regulatory pathways in the sea urchin embryo
Summary: Molecular screens and knockdown studies reveal that SoxC and Brn1/2/4 function sequentially during neurogenesis in sea urchin embryos and are required for the differentiation of all neurons.
- Two Forkhead transcription factors regulate cardiac progenitor specification by controlling the expression of receptors of the fibroblast growth factor and Wnt signaling pathways
Summary: Checkpoint suppressor homologue and Jumeau, which are known to govern cardiac progenitor cell divisions, play additional, mutually redundant roles in specifying cardiac mesoderm in Drosophila.
- Prox1 and fibroblast growth factor receptors form a novel regulatory loop controlling lens fiber differentiation and gene expression
Summary: RNA-seq and the analyses of mutant mice reveal that Prox1 functions as a global regulator of lens fiber cell gene expression and acts in a feedback loop to control the expression of FGF receptors.
- A new level of plasticity: Drosophila smooth-like testes muscles compensate failure of myoblast fusion
Summary: Drosophila testes muscles arise from stem cells and can compensate for fusion defects to safeguard fertility; this plasticity may compensate for the observed lack of satellite cells in Drosophila.
- Dual function of Bmpr1a signaling in restricting preosteoblast proliferation and stimulating osteoblast activity in mouse
Summary: The genetic deletion of Bmpr1a in mice reveals a dual function for BMP signaling in restricting preosteoblast proliferation and promoting osteoblast activity, probably via regulation of mTORC1.
- c-Raf promotes angiogenesis during normal growth plate maturation
Summary: The chondrocyte-specific ablation of c-Raf in mice results in a delay in vascular invasion and growth plate maturation due to increased ubiquitin-dependent degradation of VEGF.
- Crim1 regulates integrin signaling in murine lens development
Summary: Crim1, a type I transmembrane protein, acts in lens epithelial cells where it colocalizes with and regulates the levels of active β1 integrin to control cell adhesion during mouse lens morphogenesis.