Research Interests

Research in my laboratory is directed towards achieving an understanding of the mechanisms underlying the regulation of expression of environmentally-responsive genes. Studies of nutritionally-sensitive, heat shock- and oxidative stress-inducible genes are being conducted employing the filamentous fungus, Neurospora crassa, as a model system.

The heat shock genes (hsp) are expressed rapidly upon exposure to hyperthermia and their products protect the cells from the resulting damage. Major structural genes of the heat shock regulon (hsp70 and hsp80) have been cloned and their chromosomal locations determined. Trans-acting factors controlling transcription are being investigated by direct analysis of DNA:protein interactions and cis-acting promoter sites are being charted by deletion analysis and by expression in vivo of reporter genes fused to the hsp gene promoters. The major stress-responsive genes under investigation encode molecular chaperones, promoting the correct folding and oligomeric assembly of cytosolic proteins.

Analysis of the function(s) of these genes is being conducted by isolation of "functional" deletions by transformation of cells with plasmids harbouring the requisite gene, followed by genetic crosses. Due to premeiotic inactivation of duplicated genes, progeny strains "deficient" in a specific gene are generated. The contribution of the Hsps toward thermotolerance and cell viability is assessed by reintroduction of the intact genes and mutants into the deficient cells. These studies will provide vital information on the molecular basis of thermotolerance and gene expression regulation.

 

Selected publications

• Senczuk, A.M., Machwe, A., and Kappor, M. 2003. High constitutive peroxidase activity and constitutive thermotolerance in Neurospora crassa. Mycoscience 44: 129-137.
• Kapoor, M., Curle, C.A., Kalia, S. and Y. Achari. 2002. Minimal promoter for the NAD+-specific glutamate dehydrogenase gene of Neurospora crassa. Biochem. Cell. Biol. 80: 177-188.
• Britton, M.E. and M. Kapoor. 2002. The oligomeric state, complex formation, and chaperoning activity of Hsp70 and Hsp80 of Neurospora crassa. Biochem. Cell Biol. 80: 797-809.
• Machwe, A., Senczuk, A.M. and M. Kapoor. Induction profiles and properties of a novel stress-induced peroxidase in Neurospora crassa. Mycoscience 43: 103-111.
• Girvitz, T.L., P.O. Ouimet and M. Kapoor. (2000). Heat shock protein 80 of Neurospora crassa: sequence analysis of the gene and expression during asexual phase. Can. J. Microbiol. 46: 981-991.
• Ouimet, PM. And M. Kapoor. 1999. Nucleotide binding and hydrolysis properties of Neurospora crassa cytosolic molecular chaperones, Hsp70 and Hsp80, heat-inducible members of the eukaryotic stress-70 and -90 families. Biochem. Cell Biol. 77: 89-99,
• Ouimet, P.M. and M. Kapoor. 1998. Analysis of complex formation between Hsp80 and Hsp70, cytosolic molecular chaperones of Neurospora crassa, by enzyme-linked immunosorbent assays (ELISA). Biochem. Cell. Biol. 76: 97-106.
• Freitag, D.G., P.M. Ouimet, T.L. Girvitz and M. Kapoor. 1997. Heat shock protein 80 of Neurospora crassa, a cytosolic molecular chaperone of eukaryotic stress 90 family, interacts directly with heat shock protein 70. Biochemistry. 36: 10221-10229.
• Vijayaraghavan, Y. and M. Kapoor. 1996. Repeat-induced point mutations of Hsp80 gene of Neurospora crassa: Methylation of duplicated DNA sequences in the vegetative state. Biochem. Cell Biol. 74: 41-50.
• Patterson, N.A. and M. Kapoor. 1996. Detection of plasmid-like DNA and double-stranded RNA elements in some Canadian isolates of the oilseed rape pathogen Leptosphaeria maculans. Can. J. Microbiol. 42: 977-982.
• Chakraborty, B.N., P.M. Ouimet, G.M. Sreenivasan, C.A. Curle and M. Kapoor. 1995. Sequence repeat-induced disruption of the major heat-inducible Hsp 70 gene of Neurospora crassa. Current Genetics. 29: 18-26.