Condensin I is required for faithful meiosis in Drosophila males.

The heteropentameric condensin complexes play vital roles in the formation and faithful segregation of mitotic chromosomes in eukaryotes. While the different contributions of the two common condensin complexes, condensin I and condensin II, to chromosome morphology and behavior in mitosis have been thoroughly investigated, much less is known about the specific roles of the two complexes during meiotic divisions. In Drosophila melanogaster, faithful mitotic divisions depend on functional condensin I, but not on condensin II.

Condensin I subunit Cap-G is essential for proper gene expression during the maturation of post-mitotic neurons.

Condensin complexes are essential for mitotic chromosome assembly and segregation during cell divisions, however, little is known about their functions in post-mitotic cells. Here we report a role for the condensin I subunit Cap-G in neurons. We show that, despite not requiring condensin for mitotic chromosome compaction, post-mitotic neurons express Cap-G.

The cohesin subunit Rad21 is required for synaptonemal complex maintenance, but not sister chromatid cohesion, during Drosophila female meiosis.

Replicated sister chromatids are held in close association from the time of their synthesis until their separation during the next mitosis. This association is mediated by the ring-shaped cohesin complex that appears to embrace the sister chromatids. Upon proteolytic cleavage of the α-kleisin cohesin subunit at the metaphase-to-anaphase transition by separase, sister chromatids are separated and segregated onto the daughter nuclei.

Functional dissection of the Drosophila melanogaster condensin subunit Cap-G reveals its exclusive association with condensin I.

The heteropentameric condensin complexes have been shown to participate in mitotic chromosome condensation and to be required for unperturbed chromatid segregation in nuclear divisions. Vertebrates have two condensin complexes, condensin I and condensin II, which contain the same structural maintenance of chromosomes (SMC) subunits SMC2 and SMC4, but differ in their composition of non-SMC subunits. While a clear biochemical and functional distinction between condensin I and condensin II has been established in vertebrates, the situation in Drosophila melanogaster is less defined.