IN THIS ISSUE
Direct lineage reprogramming via pioneer factors; a detour through developmental gene regulatory networks
Summary: This Hypothesis explores pioneer transcription factor-driven direct lineage reprogramming between mature cell states, proposing that this depends on reversion to a developmentally immature state.
STEM CELLS AND REGENERATION
Functional analysis of AEBP2, a PRC2 Polycomb protein, reveals a Trithorax phenotype in embryonic development and in ESCs
Highlighted article: Targeted mutation of the Polycomb protein AEBP2 in mouse provides evidence for a role for this factor in defining the composition and activity of PRC2 complexes.
Summary: Denervation of the amputated axolotl limb prevents regeneration. The neuronally secreted protein Neuregulin-1 is required for regeneration, and can induce it in denervated limbs.
DISC1 regulates astrogenesis in the embryonic brain via modulation of RAS/MEK/ERK signaling through RASSF7
Highlighted article: Astrocyte-specific depletion of the schizophrenia-associated gene Disc1 in the developing mouse and in vitro leads to impaired astrogenesis due to disrupted RAS/ERK signaling.
Summary: During mouse cortical development, the Arp2/3 actin branching complex regulates process formation and the maintenance of radial glial cell polarity, as well as affecting neuronal migration.
Highlighted article: The RNA-binding protein IMP2 is enriched in developing axons, interacts with a network of axon guidance-related mRNAs, and is required for normal axon pathfinding in mouse embryos.
The Drosophila neurogenin Tap functionally interacts with the Wnt-PCP pathway to regulate neuronal extension and guidance
Summary: Mammalian neurogenins are proneural factors, but the Drosophila homolog Tap is not, instead acting to prevent axonal outgrowth, likely by regulating the planar cell polarity pathway via Dishevelled.
The methyltransferase Setdb1 is essential for meiosis and mitosis in mouse oocytes and early embryos
Highlighted article: The H3K9 methyltransferase Setdb1 is required during mouse oogenesis to control gene expression, restrain expression of endogenous retroviruses and enable successful progression through meiosis and mitosis.
Summary: In the female gametophyte, the synergid cell is required to attract the pollen tube, and then degenerates. Its death, and pollen tube bursting, is controlled by the VDD and VAL transcription factors.
Drosophila Condensin II subunit Chromosome-associated protein D3 regulates cell fate determination through non-cell-autonomous signaling
Summary: The chromatin-organizing protein CAP-D3 maintains EGFR signaling in the developing Drosophila wing disc, identifying a key transcriptional regulatory network influencing vein development.
LGN plays distinct roles in oral epithelial stratification, filiform papilla morphogenesis and hair follicle development
Summary: In different regions of the mouse oral epithelium, differential subcellular localization of the spindle orientation protein LGN regulates distinct patterns of cell division.
Delineation of proteolytic and non-proteolytic functions of the membrane-anchored serine protease prostasin
Summary: The serine protease prostasin triggers a cell surface-associated proteolytic pathway that regulates epithelial development in mouse, independent of its own proteolytic activity.
Summary: During mouse retinogenesis, the Sip1 transcription factor participates in the gene regulatory network that controls timely cell cycle exit and differentiation of a subset of retinal progenitor cells.
Quadruple zebrafish mutant reveals different roles of Mesp genes in somite segmentation between mouse and zebrafish
Summary: The analysis of zebrafish quadruple Mesp mutants identifies conserved and species-specific mechanisms by which the temporal periodicity of the somitogenesis clock is interpreted.
Summary: MRTFs are regulators of actin cycling and cytoskeletal gene expression. Loss of MRTFs in the mouse skeletal muscle causes muscle hypoplasia due to defects in sarcomere formation.
TECHNIQUES AND RESOURCES
Single-molecule RNA detection at depth by hybridization chain reaction and tissue hydrogel embedding and clearing
Summary: Single-molecule hybridization chain reaction, combined with tissue clearing, allows the near-quantitative and spatially localized detection of mRNAs in thick tissue samples.
Leapfrogging: primordial germ cell transplantation permits recovery of CRISPR/Cas9-induced mutations in essential genes
Summary: Germ cell transplantation from mutagenized F0 Xenopus tropicalis embryos into wild-type hosts mitigates founder lethality, allowing generation of mutant lines. This technique should be transferable to other species.