Ronald E. Yasbin, Ph.D.

Dean, College of Sciences

Laboratory:
White Hall 127
702-895-2075

Office:
702-895-3487

Current Research

Bacillus subtilis is a model organism for studying cellular differentiation and development. We previously established in our chromosomal reversion assay system that an adaptive, mutagenic process occurs in stationary phase B. subtilis cells under stress. This phenomenon is associated with transcription factors ComA and ComK, which are required for the post-exponential development of a subpopulation of competent cells. It does not require a functional RecA protein. Furthermore, the absence of YqjH, a putative Y-superfamily error-prone DNA polymerase, significantly reduces reversion rates at the hisC952 allele during stationary phase. A decrease in a functional MMR protein, MutS, results in increasing reversion rates. This evidence supports the hypothesis that multiple mechanisms are involved in generating stationary phase mutations.

We are currently examining the role of transcription and transcription-associated proteins in stationary phase mutagenesis. In B. subtilis, the transcription factors Mfd, GreA and NusA interact with RNA polymerase to facilitate elongation or termination. We have assayed the effects of mfd and greA disruptions individually on the accumulation of reversions in stationary phase. In the absence of these factors, the accumulation of reversions decreases dramatically. The results of these assays strongly support the idea that transcription factors modifying RNA polymerase activity are involved in stationary phase mutagenesis.

About Dr. Yasbin

Dr. Yasbin is a microbial geneticist who focuses on DNA repair mechanisms in Bacillus subtilis and on how these processes, among others, are involved in bacterial adaptation to stressful environments. He is committed to excellence in science education and to enhancing research opportunities and infrastructure at UNLV.

Dr. Yasbin welcomes both undergraduate and graduate students into his laboratory and invites them to make a yearly pilgrimage to the Wind River Conference in Prokaryotic Biology, where they have an opportunity to interact with other scientists and students and to present the results of their research. He is currently collaborating with Dr. Mario Pedraza-Reyes (University of Guanajuato) and Dr. Eduardo Robleto (UNLV) to elucidate the mechanisms involved in stationary phase mutagenesis in B. subtilis.