Functional analysis of three adjacent open reading frames from the right arm of yeast chromosome XVI.

A 7.24 kb genomic DNA fragment from the yeast Saccharomyces cerevisiae chromosome XVI was isolated by complementation of a new temperature-sensitive mutation tsa1. We determined the nucleotide sequence of this fragment located on the right arm of chromosome XVI.

Phenylalanine- and tyrosine-auxotrophic mutants of Saccharomyces cerevisiae impaired in transamination.

This paper reports the first isolation of Saccharomyces cerevisiae mutants lacking aromatic aminotransferase I activity (aro8), and of aro8 and aro9 double mutants which are auxotrophic for both phenylalanine and tyrosine, because the second mutation, aro9 affects aromatic aminotransferase II. Neither of the single mutants displays any nutritional requirement on minimal ammonia medium. In vitro, aromatic aminotransferase I is active not only with the aromatic amino acids, but also with methionine, alpha-aminoadipate, and leucine when phenylpyruvate is the amino acceptor, and in the reverse reactions with their oxo-acid analogues and phenylalanine as the amino donor.

Cis- and trans-acting elements determining induction of the genes of the gamma-aminobutyrate (GABA) utilization pathway in Saccharomyces cerevisiae.

In S. cerevisiae, gamma-aminobutyrate (GABA) induces transcription of the UGA genes required for its utilization as a nitrogen source. Analysis of the 5' region of the UGA1 and UGA4 genes led to the identification of a conserved GC-rich sequence (UASGABA) essential to induction by gamma-aminobutyrate.

Cloning and expression of the UGA4 gene coding for the inducible GABA-specific transport protein of Saccharomyces cerevisiae.

Transport of 4-aminobutyric acid (GABA) in Saccharomyces cerevisiae is mediated by three transport systems: the general amino acid permease (GAP1 gene), the proline permease (PUT4 gene), and a specific GABA permease (UGA4 gene) which is induced in the presence of GABA. The UGA4 gene encoding the inducible GABA-specific transporter was cloned and sequenced and its expression analyzed. The predicted amino acid sequence shows that UGA4 encodes a 62 kDa protein having 9-12 putative membrane-spanning regions.

The UGA43 negative regulatory gene of Saccharomyces cerevisiae contains both a GATA-1 type zinc finger and a putative leucine zipper.

The UGA43 gene of Saccharomyces cerevisiae is required for repression of inducible genes involved in the utilization of 4-aminobutyric acid (GABA) or urea as nitrogen sources. The UGA43 gene has been cloned by complementation of a uga43 mutation. The N-terminal region of the UGA43 protein is very similar to the DNA-binding zinc-finger region typical of the GATA regulatory factor family in vertebrates.