Department of Biology, Institute of Biology and Biotechnology, University of Rzeszów, 35-601 Rzeszów, Poland.
Department of Medical Genetics, Institute of Mother and Child, 01-211 Warsaw, Poland.
Cells. 2022 Sep 1;11(17):2727. doi: 10.3390/cells11172727.
Microcephaly presents in neurodevelopmental disorders with multiple aetiologies, including bi-allelic mutation in , a component of the biologically fundamental and conserved microtubule-nucleation complex, γ-TuRC. Elucidating underlying principles driving microcephaly requires clear phenotype recapitulation and assay reproducibility, areas where go-to experimental models fall short. We present an alternative simple vertebrate/invertebrate dual system to investigate fundamental -related processes driving human microcephaly and associated developmental traits. We show that antisense morpholino knockdown (KD) of the homolog, , recapitulates human -associated microcephaly. Co-injection of wild type mRNA pre-empts microcephaly in 55% of KD zebrafish larvae, confirming causality. Body shortening observed in morphants is also rescued. Mitotic marker (pH3) staining further reveals aberrantly accumulated dividing brain cells in microcephalic KD morphants, indicating that depletion disrupts normal mitosis and/or proliferation in zebrafish neural progenitor brain cells. double knockouts (KO) for homologs also develop microcephalic brains with general microsomia. Exacerbated linked developmental aberration versus single mutations strongly suggests interactive or coinciding gene functions. We infer that and affect brain size similarly to and recapitulate both microcephaly and microcephaly-associated developmental impact, validating the zebrafish/fly research model for human microcephaly. Given the conserved cross-phyla homolog function, the data also strongly support mitotic and/or proliferative disruption linked to aberrant microtubule nucleation in progenitor brain cells as key mechanistic defects for human microcephaly.
小头畸形表现为多种病因的神经发育障碍，包括生物基本和保守的微管成核复合物γ-TuRC 的双等位基因突变。阐明导致小头畸形的潜在原则需要明确的表型再现和可重复的检测，而这些正是传统实验模型的不足之处。我们提出了一种替代的简单脊椎动物/无脊椎动物双重系统，以研究驱动人类小头畸形和相关发育特征的基本相关过程。我们表明， 同源物的反义形态发生素敲低 (KD) 可重现人类小头畸形相关的小头畸形。野生型 mRNA 的共注射可预先阻止 55% KD 斑马鱼幼虫的小头畸形，从而证实了因果关系。在形态发生素中观察到的身体缩短也得到了挽救。有丝分裂标记物 (pH3) 染色进一步揭示了小头畸形 KD 形态发生素中异常积累的分裂脑细胞，表明 耗竭破坏了斑马鱼神经祖细胞的正常有丝分裂和/或增殖。 同源物的双敲除 (KO) 也会导致小头畸形的大脑伴有全身性的微小畸形。与单个突变相比，增强的相关发育异常强烈表明基因功能的相互作用或巧合。我们推断 和 对大脑大小的影响类似于 和 ，可重现小头畸形和小头畸形相关的发育影响，从而验证了斑马鱼/蝇研究模型在人类小头畸形中的适用性。鉴于跨门同源物的保守功能，这些数据还强烈支持与祖细胞脑细胞中异常微管成核相关的有丝分裂和/或增殖中断是人类小头畸形的关键机制缺陷。
