The chsA gene, encoding a class-I chitin synthase from Ampelomyces quisqualis.

Degenerate oligodeoxyribonucleotide primers, designed on the basis of conserved regions of the chitin synthase gene family, were used to amplify a fragment of the Ampelomyces quisqualis (Aq) chsA gene. Subsequently, the PCR product was used as a probe in order to identify and isolate genomic clones harboring the entire chsA gene. Aq chsA is 2786-nt long, has one intron and encodes a 910-amino-acid polypeptide belonging to the class-I chitin synthases. Low-stringency Southern hybridizations to Aq genomic DNA provided evidence for the presence of additional DNA fragments resembling chsA in the fungal genome, suggesting the presence of a multigene family of chitin synthases in Aq.