K. Muniyappa
CSIR Bhatnagar Fellow & Honorary Professor

Ph.D.: Indian Institute of Science, Bangalore, India.

Post-doctoral research:

Yale University School of Medicine, New Haven, USA University of Georgia, Athens, USA

Year of Joining: December 23, 1987

Email:kmbc@iisc.ac.in

Biochemical and structural analysis of Saccharomyces cerevisiae synaptonemal complex (SC) proteins.Meiosis is a specialized form of cell division during which the diploid cells undergo a single round of DNA replication followed by two rounds of chromosome segregation to produce haploid gametes. At the center of this process is the SC, a dense, evolutionarily conserved, proteinaceous superstructure that functions as a “molecular zipper” to juxtapose homologous chromosomes, one from each parent, to pair up and exchange genetic material by crossing over. A growing body of evidence suggests that defects in the SC leads to infertility, recurrent miscarriages and chromosome aneuploids such as the Down’s syndrome, in addition to germline cancers. How the components of SC exert their function has been hotly debated from multiple perspectives. Our research has focused on delineating the structure-function relationships of S. cerevisiae SC proteins, the functional relationships among them, and the underlying molecular mechanism(s) by which these proteins may orchestrate meiotic chromosome synapsis and recombination. We have employed an ensemble of molecular biological and single molecular approaches to characterize the activities of Hop1 and Red1, the two meiosis-specific proteins of the SC axial element of S. cerevisiae.

Physiologically important small molecules as regulators of RecA function: The bacterial RecA protein plays a pivotal role in the repair of stalled replication forks, double-strand break repair, homologous recombination, and the SOS response. RecA is regulated at many levels. The biological activities of RecA protein is regulated by the action of a number of accessory proteins, including RecF, SSB, RecO, RecR, DinI, RecX, RdgC, PsiB, and UvrD. All of these proteins typically exert their actions on the assembly and/or activity of RecA nucleoprotein filaments through positive or negative regulatory mechanisms. To further inform our understanding of the regulation of RecA function by endogenous small molecules, the potential roles of the nucleotide second messengers and plasma membrane components were examined. Our work support the notion that cyclic di-AMP, but not cyclic di-GMP, and anionic phospholipids of the bacterial plasma membrane regulate recombination-based DNA repair and SOS response.