Three-dimensional reconstruction of abscission

脱落是胞质分裂的最后阶段，此时连接两个有丝分裂后子细胞的狭窄细胞间桥被切断。最近，我们发现了ESCRT-III依赖的细丝的螺旋内形成的HeLa细胞的细胞间的桥梁，可以驱动皮质收缩过程中的分裂。本研究计划的第一个目标是研究CEP 55和阿利克斯（ESCRT-III复合物的两个潜在上游靶向组分）和Spastin对HeLa细胞中使用电子断层扫描的凋亡的相对贡献。第二个目标是将我们的分析扩展到秀丽隐杆线虫早期胚胎。我们想回答一个基本的问题，我们提出的衰变模型在其他系统中是否守恒？使用蠕虫，我们建议在野生型胚胎中产生参考的中间阶段的3D模型，表征C。elegans ESCRT-III组分的RNA介导的干扰（RNAi），并进行电子断层扫描分阶段突变胚胎分析。预计这种比较方法将导致对解除武装过程的进一步基本结构和机制见解。

Abscission is the final stage of cytokinesis, when the narrow intercellular bridge connecting the two post-mitotic daughter cells is severed. Recently, we discovered helices of ESCRT-III-dependent fila-ments forming within the intercellular bridges of HeLa cells that could drive cortical constriction during abscission. The first goal of this research proposal is to study the relative contributions of CEP55 and ALIX, two potential upstream targeting components of the ESCRT-III complex, and Spastin, to abscission in HeLa cells using electron tomography. The second goal is to extend our analysis of abscission to the early Caenorhabditis elegans embryo. We want to answer the basic question, is our suggested model of abscission conserved in other systems? Using the worm, we propose to generate reference 3D models of intermediate stages of abscission in wild-type embryos, characterize the role of C. elegans ESCRT-III components by RNA-mediated interference (RNAi), and perform electron tomographic analyses of staged mutant embryos. It is anticipated that this comparative approach will lead to further fundamental structural and mechanistic insights into the process of abscission.