Isolation of an Ustilago maydis gene encoding 3-hydroxy-3-methylglutaryl-coenzyme A reductase and expression of a C-terminal-truncated form in Escherichia coli.

A gene encoding 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase was isolated from the maize fungal pathogen Ustilago maydis. This was accomplished by identifying cDNA and genomic clones that hybridized to an internal fragment of the gene, amplified from U. maydis genomic DNA by PCR. The nature of the gene was determined by nucleotide sequence analysis, and by comparing the derived amino acid sequence of the gene with HMG-CoA reductases from yeast, and from other organisms. The hydrophobic nature of the N-terminal region of the deduced protein sequence also supported the view that this gene encoded HMG-CoA reductase. 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 an inhibitor of mammalian HMG-CoA reductase activity.