ISOLATION OF AN USTILAGO-MAYDIS GENE ENCODING 3-HYDROXY-5-METHYLGLUTARYL-COENZYME-A REDUCTASE AND EXPRESSION OF A C-TERMINAL-TRUNCATED FORMIN ESCHERICHIA-COLI

A gene encoding 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reduct ase was isolated from the maize fungal pathogen Ustilago maydis. This was accomplished by identifying cDNA and genomic clones that hybridize d to an internal fragment of the gene, amplified from U. maydis genomi c DNA by PCR. The nature of the gene was determined by nucleotide sequ ence analysis, and by comparing the derived amino acid sequence of the gene with HMG-CoA reductases from yeast, and from other organisms. Th e hydrophobic nature of the N-terminal region of the deduced protein s equence abo supported the view that this gene encoded HMG-CoA reductas e. A C-terminal-truncated fragment of the U. maydis HMG-CoA reductase gene was shown to be expressed in Escherichia coli in a catalytically active form. The expressed protein was also shown to be sensitive to a n inhibitor of mammalian HMG-CoA reductase activity.