Studies on SOLO Working Mechanism in the Meiosis of Drosophila melanogaster

In eukaryotes, sister chromatids are closely aligned due to cohesion, a process essential for chromosome pairing and segregation during both mitosis and meiosis. A conserved cohesin complex in a ring structure is composed of four subunits, including each of these four members or their homologs, SMC1, SMC3, SCC1/RAD21/REC8, and SCC3/SA. Up to now, no REC8 homolog has been identified in the meiosis of Drosophila. SOLO is a meiotic protein required for accurate chromosome segregation, centromere cohesion, and cohesin complex localization in Drosophila meiosis. In addition, SOLO is required for synapsis and recombination in Drosophila female meiosis.

In this study, we further analyzed the working mechanism of SOLO and the SOLO-containing cohesion complex in Drosophila meiosis. SOLO C-terminal residues conserved with SCC1/ RAD21/ REC8 are essential for its chromosome localization, accurate chromosome segregation and centromere cohesion. Furthermore, yeast two-hybrid revealed that SOLO interacts with SA; in addition, it interacts with SMC1 and SMC3 with its C and N terminus, respectively. Similar to RAD21, SOLO interacts with Drosophila Separase homolog SSE based on the results from yeast two-hybrid. These results taken together support that SOLO might work as the SCC1/REC8 homolog in Drosophila meiosis.