The CYK-4 GAP domain regulates cortical targeting of centralspindlin to promote contractile ring assembly and facilitate ring dissolution.

During cytokinesis, an equatorial contractile ring partitions the cell contents. Contractile ring assembly requires an equatorial zone of active GTP-bound RhoA generated by the guanine nucleotide exchange factor ECT2. ECT2 is activated by centralspindlin, a complex composed of two molecules each of kinesin-6 and CYK4.

Hybrid incompatibility emerges at the one-cell stage in interspecies embryos.

Intrinsic reproductive isolation occurs when genetic differences between populations disrupt the development of hybrid organisms, preventing gene flow and enforcing speciation. While prior studies have examined the genetic origins of hybrid incompatibility, the effects of incompatible factors on development remain poorly understood. Here, we investigate the mechanistic basis of hybrid incompatibility in nematodes by capitalizing on the ability of females to produce embryos after mating with males from several other species.

TRIM37 employs peptide motif recognition and substrate-dependent oligomerization to prevent ectopic spindle pole assembly.

Tightly controlled duplication of centrosomes, the major microtubule-organizing centers of animal cells, ensures bipolarity of the mitotic spindle and accurate chromosome segregation. The RBCC (RING-B-box-coiled coil) ubiquitin ligase TRIM37, whose loss is associated with elevated chromosome missegregation and the tumor-prone developmental human disorder Mulibrey nanism, prevents the formation of ectopic spindle poles that assemble around structured condensates containing the centrosomal protein centrobin. Here, we show that TRIM37's TRAF domain, unique in the extended TRIM family, engages peptide motifs in centrobin to suppress condensate formation.

Cyclin B3 is a dominant fast-acting cyclin that drives rapid early embryonic mitoses.

Mitosis in early embryos often proceeds at a rapid pace, but how this pace is achieved is not understood. Here, we show that cyclin B3 is the dominant driver of rapid embryonic mitoses in the C. elegans embryo.

Automated profiling of gene function during embryonic development.

Systematic functional profiling of the gene set that directs embryonic development is an important challenge. To tackle this challenge, we used 4D imaging of C. elegans embryogenesis to capture the effects of 500 gene knockdowns and developed an automated approach to compare developmental phenotypes.