Lactam utilisation in Aspergillus nidulans: evidence for a fourth gene under the control of the integrator gene intA

Mutations in the lamA gene of Aspergillus nidulans prevent the conversion of exogenous 2-pyrrolidone (gamma-butyrolactam) to gamma-amino-n-butyrate (GABA) and also prevent the (probably analogous) utilisation of 2-piperidone (sigma-valerolactam). The lamA gene, in linkage group VIII, probably specifies a lactamase but a rôle in lactam uptake cannot be ruled out. lamA is probably under the control of the positive acting regulatory gene intA, which can integrate its expression with the expression of three other genes, specifying acetamidase, GABA transaminase, and GABA permease, respectively.