Functional analysis of an endo-1,6-β-D-glucanase gene (neg-1) from Nettrospora crassa

The 1,6-beta-D-glucanase gene (neg1) of Neurospora crassa was disrupted by repeat-induced point mutations. Sequence analysis of the neg1 gene in the R12-1 mutant showed that 9 nucleotides within the coding region of the gene changed from GC to AT. The base transition of C to A at position 662 resulted in a codon. No apparent phenotypic changes were observed in the mutant, but Congo-red, SDS, and cetyltrimethyl ammonium bromide (CTAB), which affect fungal cell walls or membranes, markedly inhibited the hyphal growth of the mutant at a concentration that does not inhibit growth in the wild type.