Text

theses

Haploid gametes are formed by a specialized cell division called meiosis. During meiosis there is one round of DNA replication, but two rounds of DNA segregation which leaves the daughter cells with half the amount of DNA as the parents. This special division is highly regulated to ensure that exactly one copy of each chromosome is included in each gamete. Once replicated the sister chromatids are held together by cohesion, and the homologous pairs are held together by the synaptonemal complex (SC). Without either of these two complexes, the chromosomes do not segregate properly at meiosis I. Mitotic cohesin is comprised of four subunits SMC1/SMC3/SCC1/SCC3, which form a ring. However, in many organisms there are meiosis specific cohesin subunits that have been discovered, such as Rec8 that substitutes for SCC1. This dissertation aims to gain insight into the meiosis specific complexes in Drosophila. There is evidence for two meiosis specific cohesin complexes functioning in Drosophila. One of the complexes is comprised of SMC1/SMC3/SOLO/SUNN. This complex has a minor role in SC assembly, but, is required for sister centromere cohesion. The other complex demonstrated is SMC1/SMC3/C(2)M/SA and is primarily responsible for SC assembly, is not involved in sister centromere cohesion and, is highly dynamic. To confirm this complex forms cohesin rings, we have made point mutations within the regions of C(2)M which are thought to mediate interactions with SMC1 and SMC3. The data collected from these mutations, to date, reveals that N-terminal amino acid residues may not be important. We are working to learn if there are alternate roles for C(2)M outside of interacting with the SMCs or if the interface between the SMCs and C(2)M is different than proposed.

ETD_8079

Ph.D.

Includes bibliographical references

by Mercedes R. Gyuricza

doi:10.7282/T39G5QP8

ETD doctoral

The author owns the copyright to this work.