Role of the Myb‐like protein Bas1p in Saccharomyces cerevisiae: a proteome analysis

Abstract

SummaryThe effect of extracellular adenine and the role of the transcriptional activator Bas1p on expression of the yeast genome was assessed by two-dimensional (2D) analysis of the yeast proteome. These data combined with LacZ fusions and northern blot analysis allow us to show that synthesis of enzymes for all 10 steps involved in purine de novo synthesis is repressed in the presence of adenine and requires BAS1 and BAS2 for optimal expression. We also show that expression of ADE12 and ADE13, the two genes required for synthesis of AMP from inosine 5Јmonophosphate (IMP), is co-regulated with the de novo pathway genes. The same combined approach, used to study histidine biosynthesis gene expression, showed that HIS1 and HIS4 expression is co-regulated with purine biosynthesis genes whereas HIS2, HIS3, HIS5 and HIS6 expression is not. This work, together with previously published data, gives the first comprehensive overview of the regulation of purine and histidine pathways in a eukaryotic organism. Finally, the expression of two pyrimidine biosynthesis genes URA1 and URA3 was found to be severely affected by bas1 and bas2 mutations in the absence of adenine, establishing a regulatory link between the two nucleotide biosynthesis pathways.

Identification of a Novel One-carbon Metabolism Regulon in Saccharomyces cerevisiae

“…Many members of the minimal one-carbon regulon are regulated by adenine levels via the Bas1p/Pho2p purine biosynthesis transcription factors (39,47). In addition, GCV1 (47) and GCV2 show decreased basal transcription in bas1 strains, and the glycine regulatory region of GCV2 includes a TGACTC motif that matches the consensus binding motif of Bas1p.…”

“…SHM1 encodes the mitochondrial SHMT, which under normal conditions contributes ϳ5% of total cellular SHMT activity (8). ADE16 encodes a minor isoform of Ade17p that is not transcriptionally co-regulated with ADE17 (37)(38)(39). The extent of the main components of the one-carbon regulon is indicated in Fig.…”

“…The Glycine Response of GCV2 Is Independent of Both BAS1 and GCN4 -Purine biosynthetic genes form a regulon controlled by the Bas1p/Pho2p transcription factors (39,40). Because many genes of the one-carbon regulon overlap with those of the Bas1p/Pho2p purine biosynthesis regulon, and the GCV2 glycine-response element contains a potential Bas1p-binding FIG.…”

Adenylosuccinate synthase from Saccharomyces cerevisiae: homologous overexpression, purification and characterization of the recombinant protein

“…Instead, transcription of the adenylosuccinate synthase gene is co-regulated in S. cere isiae with the enzymes for the synthesis of purines de no o. The transcription of these genes is efficiently repressed by adenine in the medium ; full expression requires the transcription factors BAS1 and BAS2 [33].…”

cAMP-induced Mitochondrial Compartment Biogenesis

“…The HAP4 fragment was amplified by PCR using S288C genomic DNA and oligonucleotides 5Ј-CCCGGATCCATCATGACCGCAAAGACT-3Ј plus 5Ј-CGCCTGCAGCTATTTCAAAATACTTGTACC-3Ј and was radiolabeled by random priming with Ready-To-Go DNA Labeling Beads (GE Healthcare). The ACT1 probe was prepared as described previously (25).…”