[Deletion analysis of the SUP2 gene in Saccharomyces cerevisiae].
The sup2 mutations of the yeast Saccharomyces cerevisiae or plasmid-mediated amplification of the wild type SUP2 gene lead to suppression of different types of nonsense mutations. The Sup2 protein includes a C-terminal region homologous to elongation factor EF-1 alpha and an unique N-terminal region. The SUP2 is an essential gene. The functional role of different regions of the SUP2 gene was investigated, by deleting them without disruption of the reading frame. Such constructs were maintained in yeast on episomal or centromeric plasmids. It was shown that the region, homologous to EF-1 alpha is necessary for viability, while the remaining N-terminal part is nonessential. The region of the first 154 amino acids is necessary and sufficient for the suppressor effect, caused by plasmid-mediated amplification of the SUP2 gene.