High impact information on CHA1

• We found that NHP6A/B proteins are also required for full induction of the yeast CHA1 gene [1].
• In addition, deletion of the gene-specific activator Cha4p did not affect derepression of CHA1 in cells depleted for Swh3p [2].
• Transcriptional repression of the yeast CHA1 gene requires the chromatin-remodeling complex RSC [2].
• The yeast CHA1 promoter is activated in the presence of serine or threonine [3].
• Consistent with this interpretation, artificially recruited TBP was unable to perturb nucleosome positioning via a nucleosomal binding site, in contrast to a true activator such as GAL4, or to perturb the TATA-containing nucleosome at the CHA1 promoter [4].

Biological context of CHA1

• Phenotypic suppression of ilv1 can occur by inducer-mediated transcriptional activation of the CHA1 gene [5].
• Previously, we identified two serine/threonine response elements in the CHA1 promoter, UASCHA [6].
• The cha4-1 allele causes noninducibility of a CHA1 p-lacZ translational gene fusion, indicating that Cha4p exerts its action through the CHA1 promoter [6].
• By this approach, we identified a protein-binding site of the CHA1 promoter [7].
• S1-nuclease mapping of the CHA1 mRNA ends showed a major transcription initiation site corresponding to an untranslated leader of about 19 nucleotides, while a major polyadenylation site was located about 86 nucleotides downstream from the open reading frame [8].

Associations of CHA1 with chemical compounds

• CHA1 is regulated by transcriptional induction by serine and threonine, and enables yeast to utilize the hydroxyamino acids as sole nitrogen source [5].
• CHA1 of Saccharomyces cerevisiae is the gene for the catabolic L-serine (L-threonine) dehydratase, which is responsible for biodegradation of serine and threonine [7].
• By UV irradiation of strain CH1, an adenine auxotrophic mutant, CHA1, forming red colonies was isolated [9].

Regulatory relationships of CHA1

• Thus, the H3 amino terminus is required to prevent Cha4p from activating CHA1 in the absence of inducer [3].

Other interactions of CHA1

• Threonine can also be deaminated by a second serine/threonine deaminase encoded by the CHA1 gene [5].
• We conclude that Cha4p is a positive regulator of CHA1 transcription and that Cha4p alone, or as part of a complex, is binding UASCHA [6].

Analytical, diagnostic and therapeutic context of CHA1

• Furthermore, derepression in the absence of the H3 amino terminus requires the primary activator of this promoter, Cha4p, which we show by chromatin immunoprecipitation to be constitutively bound to the CHA1 promoter in WT yeast [3].

References