Sequence comparison of a segment of the gene for 3-hydroxy-3-methylglutaryl-coenzyme A reductase in zygomycetes.

In this paper we compare the sequences of a segment of the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase gene, isolated from eleven different strains belonging to four species of the fungal order Mucorales, Parasitella parasitica, Absidia glauca, Mucor mucedo (Mucoraceae) and Blakeslea trispora (Choanephoraceae). The segment was obtained by polynucleotide-chain-reaction amplification with primers derived from conservative regions of the gene. For the species M. mucedo and P. parasitica we have obtained evidence for two different types of HMG-CoA reductase genes by hybridization of genomic DNA with the amplified fragment and by cloning and sequencing of two different fragments. The different genes from one species show a sequence similarity of around 80% at the protein sequence level, whereas sequences of the same type from different species show similarity ranging between 91-96%. The highest similarity was found between the genes of type 1 from B. trispora and M. mucedo, although these species belong to different families. Southern-blot analysis of A. glauca DNA and B. trispora DNA revealed a second copy of the genes.