cpc-2, a new locus involved in general control of amino acid synthetic enzymes in Neurospora crassa.

In Neurospora crassa starvation for single amino acids leads to derepression of enzymes in many amino acid synthetic pathways. Regulation occurs at the level of transcription via "general amino acid (or cross-pathway) control". In this paper a new regulatory gene, cpc-2, is described that specifies a positive, trans-acting effector involved in this control. This gene, located on linkage group VII, was identified by a recessive mutation, U142, which results in sensitivity for two amino acid analogues and a lack of enzyme derepression in response to amino acid limitation. It was shown that cpc-2 (U142) impairs the activation of transcription of amino acid structural genes in several biosyntheses. The only other known regulatory gene involved in general amino acid control of Neurospora is cpc-1. Transcription of the cpc-1 gene, however, is increased in response to amino acid starvation irrespective of the presence of the mutation U142.