Allantoin transport in Saccharomyces cerevisiae is regulated by two induction systems

Abstract

We show that the allantoin transport system of Saccharomyces cerevisiae responds to two induction systems, one mediated by allophanate or its analog oxalurate and the other mediated by allantoin or its analog hydantoin acetate. The effects of the two inducers were additive in strain M85. Like other allantoin pathway genes, oxalurate-mediated induction of allantoin transport required a functional DAL8I gene product. Hydantoin acetate-mediated induction of the system, on the other hand, occurred normally in dai8) mutants. This suggests that induction was not only mediated by two separate inducers, but also involved different regulatory proteins.

Requirement of upstream activation sequences for nitrogen catabolite repression of the allantoin system genes in Saccharomyces cerevisiae.

“…The fact that those sequences shown to be required for NCR are situated outside the transcribed region leads us to conclude that NCR, like induction, is a transcriptional regulatory process in S. cerevisiae, thus supporting our earlier conclusions (8,12,14,15,20,23,27).…”

“…Early genetic studies led to the now-accepted suggestion that NCR was a negatively acting process with a repressor binding site situated in the 5'-flanking region of the gene (11,16). With isolation of the allantoin and arginine system genes, we demonstrated that induction and NCR of CAR], DURJ,2, DAL4, DAL7, and DAL5 gene expression resulted in increased and decreased steady-state levels of the mRNAs encoded by these genes, respectively (8,12,20,23,27). This was consistent with the idea that both processes occur at transcription (8,12,20,23,27).…”

“…With isolation of the allantoin and arginine system genes, we demonstrated that induction and NCR of CAR], DURJ,2, DAL4, DAL7, and DAL5 gene expression resulted in increased and decreased steady-state levels of the mRNAs encoded by these genes, respectively (8,12,20,23,27). This was consistent with the idea that both processes occur at transcription (8,12,20,23,27).Recent studies of the DAL5 and DAL7 5'-flanking sequences revealed that inducibility or lack of it correlates with the composition of cis-acting elements which they possess (21, 26). The DAL5 gene, which does not respond to inducer, was found to possess a single type of element, an upstream activation sequence (UAS).…”

DAL82, a second gene required for induction of allantoin system gene transcription in Saccharomyces cerevisiae

“…Expression of several allantoin pathway genes (DAL4, DAL7, and DUR1,2) in Saccharomyces cerevisiae increases 10-to 20-fold when compounds that can be degraded to the inducer, allophanate, are added to the culture medium (4,10,36,39). A similar response is caused by the gratuitous inducer oxalurate (30).…”

“…A similar response is caused by the gratuitous inducer oxalurate (30). In contrast, when cells are provided with a readily used nitrogen source, such as asparagine or glutamine, mRNA levels drop precipitously whether or not inducer is present, a phenomenon termed nitrogen catabolite repression (4,10,25,36,39). cis-acting elements required for basal-level gene expression, response to inducer, and nitrogen catabolite repression have been shown to be situated upstream of the inducible DAL7 transcribed sequences, suggesting that regulation of the gene occurs at transcription (38).…”