Genetic evidence for the creation of a reinitiation site by mutation inside the yeast ura 2 gene.

The ura 2 gene of yeast codes for two enzymatic activities which are translated from a unique messenger RNA in the order carbamoly-phosphate synthetase (CPSase), aspartate transcarbamylase (ATCase) (Lacroute, 1968; Denis-Duphil and Kaplan, 1976). Nonsense mutations in the CPSase region cause a complete loss in ATCase activity by a total polar effect, characteristic of cukaryotic mRNA translation, and due to the unique site of protein initiation present on each messenger (Shaffer et al., 1969).