Don P. Bourque
Professor of Biochemistry, Molecular and Cellular Biology
Ph.D. 1969, Duke University
Structure, function and molecular biology of chloroplast ribosomes, molecular biology of nitrogen fixation, detoxification of xenobiotic-contaminated environments by genetically-engineered plants.
Research Interests
We study genes which code for tobacco chloroplast ribosomal proteins. Our research is aimed at understanding the coordination of expression of both nuclear and chloroplast genes involved in chloroplast ribosome biogenesis. We are: 1) examining rps12 gene expression, which requires a novel RNA processing event--trans-splicing of two different chloroplast DNA transcripts (both containing portions of the polypeptide coding regions)--to give a functional rps12 mRNA with its three exons in correct reading frames; 2) studying nuclear genes coding for chloroplast ribosomal proteins; and 3) examining mechanisms of regulation of expression of chloroplast ribosomal protein-coding genes.
Another project involves developing genetically-engineered plants to detoxify xenobiotics in the soil. Polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants which are highly toxic, probably carcinogenic, and are now found in organisms throughout the food chain, including humans. A cytochrome P-450 (PBD-2) metabolizes highly chlorinated PCBs which are particularly persistent toxins in humans. We have sequenced a cDNA coding for PBD-2. Studying transgenic plants which express the PBD-2 gene, we are engineering them for constitutive expression of PBD-2, with particular interest in expression in roots. Electron transfer between PBD-2 and plant P-450 reductase in transgenic plants may result in detoxification of PCBs. Dispersal of transgenic plants in PCB-contaminated sites will be avoided by engineering male sterile plants which express PBD-2.
Selected Publications
Bonham-Smith, P.C., and D.P. Bourque. 1990. The chloroplast genome and regulation of its expression. In: Chromosomes: Eucaryotic, Procaryotic, and Viral, Vol. II, CRC Press, Inc., pp. 179-216.
Graves, P.E., G. Elhag, P.J. Ciaccio, D.P. Bourque, and J.R. Halpert. 1990. cDNA and deduced amino acid sequence of a dog hepatic cytochrome P450IIB responsible for the metabolism of 2,2',4,4',5,5'-hexachlorobiphenyl. Arch. Biochem. Biophys. 281:106-115.
Ciaccio, P.J., P.E. Graves, D.P. Bourque, B. Glinsman-Gibson, and J.R. Halpert. 1991. cDNA and deduced amino acid sequences of a dog liver cytochrome P450 of the IIIA gene subfamily. Biochem. Biophys. Acta. 1088:319-322.
Elhag, G.A., F.J. Thomas, T.P. McCreery, and D.P. Bourque. 1992. Nuclear-encoded chloroplast ribosomal protein L12 of Nicotiana tabacum: Characterization of mature protein and isolation and sequence analysis of cDNA clones encoding its cytoplasmic precursor. Nucl. Acids Res. 20:687-697.
Elhag, G.A., and D.P. Bourque. 1992. Nucleotide and deduced amino acid sequences of cDNAs coding for Nicotiana tabacum chloroplast ribosomal protein L24. Journal of Biological Chemistry 267:21705-21711.
Elhag, G.A. and D.P. Bourque. 1992. Chloroplast ribosomal protein L27:Isolation and sequence analysis of cDNA clones from Nicotiana tabacum. Biochemistry 31:6856-6864.
Galbraith, D.W., H.J. Bohnert, and D.P. Bourque, eds. Methods in Plant Cell Biology, volumes 49 and 50, Academic Press, N.Y. (1995).