RNA Polymerase Studies

    Global sequence comparisons have shown that the genes encoding the subunit proteins of the DNA-dependant RNA polymerase (RNAP) are among the more rapidly evolving in  plastid genomes. Those of the flowering plant family Geraniaceae, which contains 4 genera (Pelargonium, Geranium, Erodium and Sarcocaulon) are evolving at an accelerated rate relative to other land plant homologues.

    Our efforts in these areas are twofold.  First, to determine the rates of sequence evolution for the 4 plastid genes (rpoA, rpoB, rpoC1 and rpoC2) in selected members of the Geraniaceae. At present we have sequences for all four genes from several genera, and have documented differential rates of change both among different genera, and among the different subunit genes.  Comparisons with other plastid homologues, ranging from the algae to tobacco, have demonstrated that the RNAP genes of Pelargonium are the most rapidly evolving yet characterized.  This effort is being conducted in collaboration with Dr. Jeff Palmer (Dept. of Biology, Indiana University) and Dr. Peter Kuhlman (Dept. of Chemistry, Denison University).

    Second, to determine the effects of this accelerated sequence evolution on the structure of the individual protein subunits (alpha, beta, beta' and beta") and on the quaternary structure of the core enzyme complex.  This effort is being conducted through homology modeling with the software package MOE (Molecular Operating System), now operating on the EKU server.  The final phase of this effort will entail the in silico docking of the core enzyme complex with a plastid DNA template containing the appropriate transcriptional regulatory elements. This effort is a collaboration with Dr. Debra Bautista (Dept. of Chemistry, EKU) and Dr. Kuhlman.

These efforts had been supported by grants from the NSF EPSCoR, and are now supported by a grant from the NIH/NCRR/INBRE #P20 - 14681.