The role of RSC in 2 micron plasmid maintenance.
Annette A. Alcasabas, James A. H. Murray
Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT, United Kingdom
The successful transmission of the 2µm circle plasmid from mother cell to daughter cell relies on the ability to overcome an intrinsic maternal inheritance bias. This is dependent on the plasmid proteins Rep1 and Rep2, the plasmid DNA locus STB, and other factors encoded within the yeast chromosomes. We have previously shown that Rsc2, a member of the RSC chromatin remodeling complex, is essential for 2µm plasmid stability. Recently, this has been attributed to Rsc2's role in recruiting the cohesin complex to the STB locus, thus, enabling the 2µm plasmid to utilise the chromosomal segregation machinery. Rsc2 is 45% identical and shares the same domain organisation with Rsc1. Rsc1 is thought to be present in an alternate form of the RSC complex, and is not required for 2µm plasmid stability. Additionally, overexpression of Rsc1 cannot suppress the rsc2 mutant's plasmid maintenance defect. We have been investigating which domains define the essential difference between Rsc1 and Rsc2 function with respect to plasmid stability. This poster summarises our initial findings using specific deletions and domain swaps between Rsc1 and Rsc2.