MOLECULAR CHARACTERIZATION OF 3 HIS4 DELETION MUTANTS IN SACCHAROMYCES-CEREVISIAE

DNA was isolated from haploid strains of Saccharomyces cerevisiae carrying three different deletions in the his4 gene, his4-15, his4-24 and his4-29, as well as a his4 point mutant and a strain carrying the HIS4 wild type gene. Samples of the DNA preparations were treated with restriction endonucleases BamHI, EcoRI, HindIII, PstI and SalI and the DNA fragments were separated according to size by agarose gel electrophoresis. A bacterial plasmid containing the yeast DNA sequences of a region including the HIS4 gene allowed the detection by molecular hybridization of the fragments in the electropherograms that contained these sequences. From the sizes of these fragments the mutations his4-15 and his4-24 were both determined to be deletions of about 0.5 kb, while his4-29 was found to be a deletion of approximately 0.9 kb. The data allowed an extension of our previously constructed cleavage map of the region as well as an approximate location of the deletions on the map. Comparisons with available data on the his4 gene and its product allowed an approximate positioning of the three functional regions of the his4 gene on the map and indicated that no large intervening sequences are present within the his4AB region. © 1979 Carlsberg Laboratory.