title: DNA damage response in microcephaly development of MCPH1 mouse model.
abstract: MCPH1 encodes BRCT-containing protein MCPH1/Microcephalin/BRIT1, mutations of which in humans cause autosomal recessive disorder primary microcephaly type 1 (MCPH1), characterized by a congenital reduction of brain size particularly in the cerebral cortex. We have shown previously that a deletion of Mcph1 in mice results in microcephaly because of a premature switch from symmetric to asymmetric division of the neuroprogenitors, which is regulated by MCPH1's function in the centrosome. Because MCPH1 has been implicated in ATM and ATR-mediated DNA damage response (DDR) and defective DDR is often associated with neurodevelopmental diseases, we wonder whether the DDR-related function of MCPH1 prevents microcephaly. Here, we show that a deletion of Mcph1 results in a specific reduction of the cerebral cortex at birth, which is persistent through life. Due to an effect on premature neurogenic production, Mcph1-deficient progenitors give rise to a high level of early-born neurons that form deep layers (IV-VI), while generate less late-born neurons that form a thinner outer layer (II-III) of the cortex. However, neuronal migration seems to be unaffected by Mcph1 deletion. Ionizing radiation (IR) induces a massive apoptosis in the Mcph1-null neocortex and also embryonic lethality. Finally, Mcph1 deletion compromises homologous recombination repair and increases genomic instability. Altogether, our data suggest that MCPH1 ensures proper neuroprogenitor expansion and differentiation not only through its function in the centrosome, but also in the DDR.
authors.affiliation: Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Jena, Germany.
authors.forename: Zhong-Wei
authors.initials: ZW
authors.lastname: Zhou
authors.forename: Alicia
authors.initials: A
authors.lastname: Tapias
authors.forename: Christopher
authors.initials: C
authors.lastname: Bruhn
authors.forename: Ralph
authors.initials: R
authors.lastname: Gruber
authors.forename: Mikhail
authors.initials: M
authors.lastname: Sukchev
authors.forename: Zhao-Qi
authors.initials: ZQ
authors.lastname: Wang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D018797:Cell Cycle Proteins; D002454:Cell Differentiation; D018385:Centrosome / Q000378:metabolism / Q000473:pathology; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism; D003598:Cytoskeletal Proteins; D004249:DNA Damage; D004260:DNA Repair; D004195:Disease Models, Animal; D017353:Gene Deletion; D055786:Gene Knockout Techniques; D042822:Genomic Instability; D051379:Mice; D008831:Microcephaly / Q000196:embryology / Q000235:genetics* / Q000473:pathology; D019579:Neocortex / Q000196:embryology / Q000473:pathology / Q000528:radiation effects; D009474:Neurons / Q000166:cytology / Q000473:pathology; D011839:Radiation, Ionizing; D011995:Recombination, Genetic
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D003598:Cytoskeletal Proteins; C547654:MCPH1 protein, mouse
keywords: CP; DDR; DNA damage response; DNA double-strand breaks; DNA single-strand breaks; DSB; EGL; HR; IR; IZ; MCPH1; MEF; MN; Microcephaly; Neurogenesis; SSB; SVZ; VZ; cortical plate; external granule layer; homologous recombination; intermediate zone; ionizing radiation; micronuclei; mouse embryonic fibroblast; subventricular zone; ventricular zone