Protein Kinase A and Mitogen-Activated Protein Kinase Pathways Antagonistically Regulate Fission Yeast fbp1 Transcription by Employing Different Modes of Action at Two Upstream Activation Sites

Abstract

A significant challenge to our understanding of eukaryotic transcriptional regulation is to determine how multiple signal transduction pathways converge on a single promoter to regulate transcription in divergent fashions. To study this, we have investigated the transcriptional regulation of the Schizosaccharomyces pombe fbp1 gene that is repressed by a cyclic AMP (cAMP)-dependent protein kinase A (PKA) pathway and is activated by a stress-activated mitogen-activated protein kinase (MAPK) pathway. In this study, we identified and characterized two cis-acting elements in the fbp1 promoter required for activation of fbp1 transcription. Upstream activation site 1 (UAS1), located approximately 900 bp from the transcriptional start site, resembles a cAMP response element (CRE) that is the binding site for the atf1-pcr1 heterodimeric transcriptional activator. Binding of this activator to UAS1 is positively regulated by the MAPK pathway and negatively regulated by PKA. UAS2, located approximately 250 bp from the transcriptional start site, resembles a Saccharomyces cerevisiae stress response element. UAS2 is bound by transcriptional activators and repressors regulated by both the PKA and MAPK pathways, although atf1 itself is not present in these complexes. Transcriptional regulation of fbp1 promoter constructs containing only UAS1 or UAS2 confirms that the PKA and MAPK regulation is targeted to both sites. We conclude that the PKA and MAPK signal transduction pathways regulate fbp1 transcription at UAS1 and UAS2, but that the antagonistic interactions between these pathways involve different mechanisms at each site.

Characterization of two different types of UDP-glucose/-galactose4-epimerase involved in galactosylation in fission yeast

“…We previously reported that the inv1 + gene that encodes invertase is repressed in the presence of glucose (Tanaka et al, 1998). The transcription of inv1 + is regulated by Scr1p, which is required for glucose repression of inv1 + (Tanaka et al, 1998) and fbp1 + (Neely & Hoffman, 2000). Similarly, Scr1p may have repressed the transcription of gal10 + in 2 % glucose medium.…”

Antagonistic Controls of Chromatin and mRNA Start Site Selection by Tup Family Corepressors and the CCAAT-Binding Factor

“…The numbers indicate the TSS position of each transcript (in base pairs) from the A residue of the first ATG in the fbp1 ϩ gene. UAS1 and UAS2 represent the binding sites of Atf1 and Rst2, respectively (24,33). (B) Northern analysis to detect fbp1 ϩ transcripts.…”

“…Php5, a component of the S. pombe CCAATbinding factor (CBF; also known as NF-Y) that possesses a histone hold domain, forms a complex with Php2/Php3 and contributes to cyc1 ϩ transcription (31,32). In addition, two cis-acting elements required for fbp1 ϩ transcription have been identified (33). Upstream activation sequence 1 (UAS1) contains a cyclic AMP response element (CRE) and is the binding site for Atf1 and its binding partner, Pcr1 (34), while UAS2 resembles the S. cerevisiae stress response element (STRE) and serves as the binding site for Rst2 (24) (Fig.…”

Cellular signalling and the complexity of biological timing: insights from the ultradian clock ofSchizosaccharomyces pombe

“…S. pombe is no exception and fundamental processes, such as the cell cycle (Wilkinson & Millar 2000) and gene expression in response to environmental signals (Neely & Ho¡man 2000;Bonnet et al 2000), are under the integrated, and mostly antagonistic, control of both pathways. The ultradian clock exerts control over the cell cycle (Kippert 2001b) and energy metabolism (Kippert & Read 2001), and it seems likely that much of this control involves the cAMP/PKA and sty1 + MAP kinase pathways.…”