Analysis of yeast ilv 1 CIS control and domain mutants.

We have identified a cis control region specific for the ilv 1 gene of Saccharomyces cerevisiae. Mutants designated ilv 1-OPc map in this control region located between arg 6 and ilv 1 and result in increased basal levels and constitutive synthesis of the ilv 1 gene products. Furthermore, ilv 1 mutants have been isolated in three different structural domains indicating that the ilv 1 gene may contain a functional intervening sequence specific for one of the two gene products.