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Naher, S.

Publications and source records attributed to Naher, S..

3 recordsLinked to original sources

Kif2C safeguards radial glial integrity to prevent cortical malformation

Radial glial cells (RGCs) generate cortical neurons and guide radial neuronal migration, yet how microtubule (MT) regulators coordinate progenitor maintenance, mitotic fidelity, and cortical architecture remains unclear. Here, we identify the MT depolymerase Kif2C/MCAK as an essential regulator of RGC integrity with relevance to human neurodevelopmental disorders. Kif2C is enriched in developing cortical RGCs and localizes to radial fibers, basal endfeet, and mitotic structures. Acute Kif2C depletion in embryonic mouse cortices disrupts RG fiber organization, impairs neuronal migration, reduces the RGC pool, and induces mitotic defects, chromosome segregation errors, DNA damage, and cell-cycle arrest. Kif2C-deficient cortices further exhibit focal pial basement membrane disruption and neuronal overmigration, resulting in a cobblestone-like cortical malformation. We identify two individuals with neurodevelopmental disorders carrying rare deleterious KIF2C variants and show that a patient-derived truncating variant fails to rescue Kif2C-deficient cortical phenotypes, implicating KIF2C dysfunction in human neurodevelopmental disorders. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/726143v1_ufig1.gif" ALT="Figure 1"> View larger version (67K): org.highwire.dtl.DTLVardef@1970844org.highwire.dtl.DTLVardef@9fe29eorg.highwire.dtl.DTLVardef@d72ddcorg.highwire.dtl.DTLVardef@103f729_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

Sex-biased transcriptome in embryonic mouse cortices under Pax6 haploinsufficiency highlights Pbdc1 as a candidate regulator

Mutations in Pax6, encoding a transcription factor essential for brain patterning and neurogenesis, have been linked to female-biased cortical malformations and behavioral abnormalities, yet the molecular basis remains unclear. Here we show that Pax6 haploinsufficiency (Sey/+) produces more pronounced sex-biased alterations in the transcriptomes and cytoarchitecture of embryonic mouse cortices than those in wild-type and homozygous mutants (Sey/Sey). Pbdc1, a previously uncharacterized X-linked gene implicated in autism, is selectively upregulated in Sey/+ females and proximity-dependent protein-protein interaction analysis reveals Pbdc1 interacts with RNA-splicing factors. Moreover, Pbdc1 overexpression reduces intermediate progenitor cells in the developing cortex. ChIP-qPCR further demonstrates Pax6 and BAF occupancy at the Pbdc1 promoter in WT embryos of both sexes and CUT&Tag shows H3K4me3 elevation selectively in Sey/+ females. Our findings indicate that partial loss of Pax6 shapes the embryonic cortical transcriptomes and cytoarchitecture in a sex-dependent manner and highlight Pbdc1 as a candidate regulator of sex-biased corticogenesis.

developmental biology↗

Kinesin family member Kif23 regulates cytokinetic division and maintains neural stem/progenitor cell pool in the developing neocortex

Accurate mitotic division of neural stem cell/progenitor cells (NSPCs) is crucial for the coordinated generation of progenitors and neurons in the developing cortex. Here, we investigated the pivotal role of Kif23, an N-kinesin motor protein, in embryonic mouse NSPCs. We found that Kif23 is highly expressed in the mitotic NSPCs within the embryonic cortex of both mouse and human. Knockdown (KD) of Kif23 led to precocious neurogenesis, attributed to an accelerated cell cycle exit, likely resulting from disrupted mitotic spindle orientation and impaired cytokinesis. Kif23 KD induced upregulation of the {gamma}-H2AX-p53-p21 signaling pathway, ultimately culminating in cytokinetic failure. Additionally, Kif23 depletion perturbed the apical surface structure of NSPCs and disrupted the proper localization of apical junctional proteins. Importantly, we demonstrated the successful rescue of Kif23 KD-induced phenotypes by introducing wild-type human KIF23, but not by a variant of KIF23 with a microcephaly-associated mutation. Our findings underscore the critical role of Kif23 in cortical development and provide novel insights into the intricate molecular mechanisms underlying pathogenesis of microcephaly. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=88 SRC="FIGDIR/small/564302v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@5488e0org.highwire.dtl.DTLVardef@1e65146org.highwire.dtl.DTLVardef@1e1ec76org.highwire.dtl.DTLVardef@16b7477_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗