Jennie Hibma

Mentor: Simmons
Molecular, Cellular, and Developmental Biology

Areas of Interest

The central dogma states that DNA is transcribed into RNA which is translated into protein. However, modifications on DNA or RNA pose a caveat to the central dogma as they effect transcription or translation. One such modification is methylation which is abundant in both DNA and diverse species of RNAs including ribosomal RNA (rRNA). In E. coli rRNA has 24 methylated residues produced by a set of 23 methyltransferases. The function of most of these methylations is unknown and knockouts of individual methyltransferases show none are essential for E. coli bacterial cell survival. However, some modifications have been shown to be necessary for proper ribosome assembly and function required for quick, proportional, and cost-effective protein synthesis. Although much is known regarding E. coli rRNA methylation, there is a lack of knowledge regarding homologous rRNA methyltransferases and their modifications in Gram-positive bacteria. My project focuses on characterizing YqxC, a putative rRNA methyltransferase, in the Gram-positive species Bacillus subtilis. Preliminary results show domain homology for binding to RNA and rRNA methyltransferase activity as well as strong differences in ∆yqxC growth phenotype displaying cold and oxidative stress sensitives and a resistance to the ribosome targeting antibiotic Streptomycin. Defining the role of this protein and the site of its modification would provide an interesting comparison with different bacterial species in conserved overlapping methylated nucleotides as well as distinct methylation sites that have resulted from independent evolution. Results from these studies will also be applied to defining roles of homologous methyltransferases in related pathogenic Gram-positive bacteria to open new areas of investigation in the regulation of stress responses and antibiotic resistance mechanisms effecting pathogenesis. In addition, this work will provide general insight into the role of rRNA methylation and the caveat this creates for the central dogma in its effect on protein synthesis.