[Mechanisms of cell division: lessons from a XXXX ].

@entity69221 @entity1 @entity2199 @entity12198 @entity70544 @entity70545 @entity69219 @entity15590 @entity69218
The mechanisms orchestrating spatial cell division control remain poorly understood. In animal cells, the position of the mitotic spindle dictates cleavage furrow placement, and thus plays a key role in governing spatial relationships between resulting daughter cells. The one-cell stage @entity2199 embryo is an attractive model system to investigate the mechanisms underlying spindle positioning in metazoans. In this review, the experimental advantages of this model system for an in vivo dissection of cell division processes are first discussed. Next, three lines of experiments that were conducted to dissect the mechanisms governing spindle positioning in one-cell stage @entity2199 embryos are summarized. First, localized laser micro-irradiations were utilized to identify the forces acting on spindle poles during anaphase. This work revealed that there is a precise imbalance of pulling forces acting on the two spindle poles, with the forces acting on the posterior spindle pole being in slight excess, thus explaining the asymmetric spindle position achieved by the end of anaphase. Second, an RNAi-based functional genomic screen was carried out to identify novel components required for generating these pulling forces. This uncovered that @entity69218 / @entity69219 , which encode GoLoco-containing proteins, as well as the previously identified Ga subunits goa-1/ @entity69221 , are required for generation of pulling forces on the spindle poles. Third, the @entity70544 locus was identified by mutational analysis to play a distinct role during anaphase spindle positioning. @entity70544 was found to encode a protein related to @entity1 @entity15590 , which is affected in @entity1 with @entity12198 . Moreover, @entity70544 is a @entity70545 that stabilizes microtubules against depolymerization. Together, these experimental approaches contribute to a better understanding of the mechanisms orchestrating spatial cell division control in metazoan organisms.
