Greg Brown received his undergraduate degree in chemistry from the University of Notre Dame and his Ph.D. in biochemistry from the Mount Sinai School of Medicine in New York City. During his postdoctoral studies at the State University of New York at Stony Brook, he investigated the evolution and mode of inheritance of mammalian mitochondrial DNA. He became an Assistant Professor in the Department of Biology in 1981, and has been a Full Professor since 1996. Since 1983 his research program has been focused on plant mitochondrial genomes, in particular on the use of the trait of cytoplasmic male sterility to explore the interactions between nuclear and mitochondrial genes in plants. He has served as Visiting Professor of Genetics at North Carolina State University and as Research Director for DNA LandMarks Inc., a plant genomics company located in St-Jean-sur-Richelieu, Quebec and a member of the BASF Plant Science Group.
Research in the Brown laboratory
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Cytoplasmic male sterility (CMS) is a maternally inherited defect in pollen production specified by novel open reading frames (ORFs) in mitochondrial DNA (mtDNA). It is thought that expression of these novel genes leads to a dysfunction in energy production, which in turn leads to male sterility. |
CMS can be suppressed by nuclear restorer of fertility (Rf) genes, which normally post-transcriptionally down-regulate expression of a novel CMS-associated mitochondrial gene. CMS / Rf systems are therefore useful for studying nuclear-mitochondrial gene interactions and for investigating the role of mitochondrial energy production in plant development. Research in the Brown lab is directed towards the study of cytoplasmic male sterility in the canola plant, Brassica napus. They have identified the novel mitochondrial genes that specify CMS in two such systems and have used positional cloning to isolate and characterize the nuclear restorer gene, Rfo, for a third system, ogu. Rfo, like other recently isolated restorer genes, has been found to belong to a very large plant gene family encoding proteins with multiple copies of a degenerate sequence, the PPR domain. It is thought that PPR proteins may function as sequence specific RNA binding proteins. The Brown lab is investigating how PPR/restorer genes regulate expression of their cognate ORF-specifying mRNAs. In addition, they have recently discovered that certain nuclear genes involved in stamen development are mis-expressed in CMS plants and are currently exploring the mechanistic basis of this observation. |
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Selected Publications
Geddy, R.G., Brown, G.G. (2007) Genes encoding pentatricopeptide repeat proteins are not conserved in location in plant genomes and may be subject to diversifying selection. BMC Genomics 8:13-26
Formanová, N., Li, X.-Q., Ferrie, A.M.R., DePauw, M., Keller, W.A., Landry, B. and Brown, G.G. (2006) Towards positional cloning in Brassica napus: generation and analysis of doubled haploid B. rapa possessing the B. napus pol CMS and Rfp nuclear restorer gene. Plant Mol. Biol., in press.
Geddy, R., Mahé, L. and Brown, G.G. (2005) Cell-specific regulation of a Brassica napus CMS-associated gene by a nuclear restorer with related effects on a floral homeotic gene promoter. Plant J. 41: 333-345.
Brown, G.G., Formanova, N., Jin, H., Wargachuk, R., Dendy, C., Patil, P., Laforest, M., Zhang, J., Cheung, W.Y., Landry, B.S. (2003) The radish Rfo restorer gene of Ogura cytoplasmic male sterility encodes a protein with multiple pentatricopeptide repeats. Plant J. 35: 262-72.
Menassa, R., L'Homme, Y. & Brown, G.G. (1999) Post-transcriptional and developmental regulation of a CMS-associated mitochondrial gene region by a nuclear restorer gene. Plant J. 17: 491-499.