Paul D. Gollnick, Ph.D.

Research

RNA-protein interactions are crucially important in many biological processes. My research involves investigating RNA-protein interactions involved in regulating gene expression. The model system we are studying is the tryptophan biosynthetic (trp) operon from Bacillus subtilis and several other related Bacilli. A novel form of attenuation controls transcription this operon. Two alternative RNA secondary structures regulate transcription termination in an untranslated leader region upstream of the structural genes. A trans-acting regulatory protein called TRAP (trp RNA-binding Attenuation Protein) controls which RNA structure forms. In the presence of tryptophan, TRAP is activated to bind to a specific target in the leader RNA. This binding results in formation of the transcription terminator, thereby halting expression of the operon. In the absence of tryptophan, TRAP does not bind RNA and the alternative antiterminator structure forms allowing expression of the operon. We have shown that TRAP protein has a unique structure consisting of 11 identical 75 amino acid subunits arranged in a ring. Future studies will involve characterizing the effect of TRAP binding on trp leader RNA structure and further investigating the mechanism by which TRAP regulates gene expression in vivo as well as investigating the possibility that other organisms use this type of gene regulation.