IN THIS ISSUE
DEVELOPMENT AT A GLANCE
Summary: This Review discusses the various cell types that constitute the mammary gland, highlighting how they arise and differentiate, and how the microenvironment influences their development.
STEM CELLS AND REGENERATION
Highlighted article: Transcriptional cross regulation between CLAVATA1 family receptor kinases operates in the stem cell niche, thereby explaining the apparent genetic redundancy amongst these receptor kinases.
Highlighted article: Gata2b marks a distinct population of embryonic endothelial cells that gives rise to hematopoietic stem cells and is required for the hemogenic potential of these cells.
Summary: The zinc finger protein teashirt is a transcriptional target of Wnt signaling and is required for Wnt-mediated specification of cell fate during regeneration in planarians.
Summary: The concerted actions of Sxl and bam allow Drosophila female germline stem cells to remember their sexual identity as they differentiate, thereby preventing the risk of tumor formation.
Highlighted article: Even though its function is not normally required for sex determination in mammals, Dmrt1 is able to drive sex reversal in XX mice, suggesting that it has retained sex-determining function.
Eph-Pak2a signaling regulates branching of the pharyngeal endoderm by inhibiting late-stage epithelial dynamics
Summary: Eph and Wnt signaling act through the Pak2a kinase to modulate intercellular adhesion and terminate branch outgrowth during pharyngeal pouch formation in the zebrafish head.
Summary: A zebrafish model for the human ectopic mineralisation disorders, PXE and GACI, reveals how mineralisation is regulated by the transporter protein ABCC6, vitamin K and warfarin.
Drosophila MAGI interacts with RASSF8 to regulate E-Cadherin-based adherens junctions in the developing eye
Highlighted article: The apical scaffold protein Magi regulates localization of the polarity protein Bazooka and hence E-cadherin deposition and adherens junction remodelling in Drosophila eye epithelial cells.
Summary: The transcription factor Lhx9 is sufficient to drive the specification of zebrafish and mouse hypocretin-expressing neurons, the neuron type that is affected in narcolepsy.
Summary: Grhl2, a member of the Grainyhead family of transcription factors, controls a trophoblast gene program that is essential for normal development of the mouse placental labyrinth.
Summary: The tethering of zebrafish otoliths, which are important for balance and hearing in fish, occurs in two stages that are dependent on genes that have been implicated in human deafness.
Summary: The serpin PN1, which is transcriptionally activated by FGF signals, inhibits the protease HtrA1 and prevents syndecan-4 degradation to restrict FGF signaling during Xenopus head development.
Summary: Interactions between Tbx6, Mesp-b and Ripply1, which are known regulators of somite boundary formation, also control spatiotemporal aspects of skeletal myogenesis in zebrafish embryos.
Summary: Articular and transient cartilage cells derive from the same cell population, and a strategically placed domain of Noggin activity regulates their differential differentiation programs in mice.
Summary: HDAC1 and 2 perform redundant yet essential functions during ureteric bud branching, controlling cell proliferation and survival, and regulating Wnt signalling and p53 acetylation.
TECHNIQUES AND RESOURCES
Second-generation Notch1 activity-trap mouse line (N1IP::CreHI) provides a more comprehensive map of cells experiencing Notch1 activity
Summary: A novel and sensitive Notch1 activity-trap mouse line allows cells experiencing low levels of Notch1 activation to be mapped throughout development.