The Neurospora crassa chs-2 gene encodes a non-essential chitin synthase

Chitin is a structural component of morphologically distinct structures assembled during various phases of growth and development in filamentous fungi. In Neurospora crassa, at least three different DNA fragments related to chitin synthase have been identified. In this study we cloned, sequenced and characterized the chitin synthase 2 structural gene (designated chs-2). The amino acid sequence deduced from the cloned chs-2 genomic DNA fragments is very similar to that of chitin synthase genes isolated from other fungi. Inactivation of the N. crassa chs-2 gene by repeat-induced point (RIP) mutation produced progeny which under standard growth conditions were indistinguishable from the wild-type. However, a significant reduction in chitin synthase activity and increased sensitivity to the phosphatidylcholine biosynthesis inhibitor edifenphos are characteristic of the chs-2(RIP) strain.