Dr. Jayaram's research is focused on the Saccharomyces cerevisiae plasmid 2-micron circle—a small, high-copy extrachromosomal selfish DNA element with chromosome-like stability.
Plasmid persistence is accomplished by a deceptively simple partitioning system consisting of two plasmid-coded proteins and a cis-acting partitioning locus. The partitioning system promotes the tethering of plasmid sisters formed by replication to sister chromatids, and 1:1 plasmid segregation by a hitchhiking mechanism.
Copy number maintenance utilizes DNA amplification promoted by the plasmid-coded Flp site-specific recombinase. Amplification is initiated by a replication-coupled DNA inversion reaction. Plasmid gene expression circuitry is fine-tuned for prompt amplification response when needed, without the risk of runaway increase in copy number.
Our research interests span mechanisms of (a) DNA rearrangements mediated by Flp and other site-specific recombinases, (b) chromosome-coupled plasmid segregation, and (c) in vivo regulation of Flp levels/activity to prevent inappropriate plasmid amplification.
In summary, we wish to unveil the interplay of plasmid- and host-encoded mechanisms that promote their nearly conflict-free coexistence over evolutionary times.