美国加州大学Mustafa G. Aydogan研究团队发现没有细胞核的细胞质分裂周期和有丝分裂的CDK/周期蛋白复合物。相关论文于2023年10月12日发表在《细胞》杂志上。

他们证明在果蝇胚胎中，细胞质可以在没有细胞核和有丝分裂CDK/细胞周期蛋白复合物的情况下重复分裂。Cdk1通常会减慢原本更快的细胞质分裂周期，将其与核分裂结合，当解耦时，细胞质在有丝分裂前开始分裂。在发育中的胚胎中，CDK/细胞周期蛋白活性可以激活纺锤体等有丝分裂微管(MT)组织者，在没有中心体(间期MT的主要组织者)的情况下，细胞质分裂也可以发生。然而，中心体在缺乏CDK/细胞周期蛋白活性的情况下变得必不可少，这意味着细胞质可以利用基于中心体的间期或CDK/细胞周期蛋白依赖的有丝分裂MT来促进分裂。

最后，他们提出的证据表明，自主细胞质分裂发生在未受干扰的苍蝇胚胎发生过程中，它们可能有助于在囊胚形成过程中挤出有丝分裂停滞的细胞核。他们假设细胞质分裂发生在周期中，由一个尚未发现的时钟机制控制，该机制独立于CDK/周期蛋白复合物。

据介绍，细胞质分裂被认为依赖于细胞核分裂和有丝分裂信号。

附：英文原文

Title: Cytoplasmic division cycles without the nucleus and mitotic CDK/cyclin complexes

Author: Anand Bakshi, Fabio Echegaray Iturra, Andrew Alamban, Miquel Rosas-Salvans, Sophie Dumont, Mustafa G. Aydogan

Issue&Volume: 2023/10/12

Abstract: Cytoplasmic divisions are thought to rely on nuclear divisions and mitotic signals. We demonstrate in Drosophila embryos that cytoplasm can divide repeatedly without nuclei and mitotic CDK/cyclin complexes. Cdk1 normally slows an otherwise faster cytoplasmic division cycle, coupling it with nuclear divisions, and when uncoupled, cytoplasm starts dividing before mitosis. In developing embryos where CDK/cyclin activity can license mitotic microtubule (MT) organizers like the spindle, cytoplasmic divisions can occur without the centrosome, a principal organizer of interphase MTs. However, centrosomes become essential in the absence of CDK/cyclin activity, implying that the cytoplasm can employ either the centrosome-based interphase or CDK/cyclin-dependent mitotic MTs to facilitate its divisions. Finally, we present evidence that autonomous cytoplasmic divisions occur during unperturbed fly embryogenesis and that they may help extrude mitotically stalled nuclei during blastoderm formation. We postulate that cytoplasmic divisions occur in cycles governed by a yet-to-be-uncovered clock mechanism autonomous from CDK/cyclin complexes.

DOI: 10.1016/j.cell.2023.09.010

Source: https://www.cell.com/cell/fulltext/S0092-8674(23)01031-0