Schizosaccharomyces pombe pcr1⁺ Encodes a CREB/ATF Protein Involved in Regulation of Gene Expression for Sexual Development

Abstract

The Schizosaccharomyces pombe pcr1 gene encodes a bZIP protein that apparently belongs to the cyclic AMP response element (CRE)-binding protein/activating transcription factor family. The deduced pcr1 gene product consists of 171 amino acid residues and is most similar to the mammalian CRE-BP1. A glutathione S-transferase-Pcr1 fusion protein produced in Escherichia coli was able to bind specifically to the CRE motif in vitro. Analysis with anti-Pcr1 serum suggested that Pcr1 is included in the major CRE-binding factors present in the S. pombe cell extract. Disruption of the pcr1 gene was not lethal, but the disruptant showed cold-sensitive growth on rich medium. The disruptant was also inefficient in mating and sporulation, though it was not completely sterile. Expression of the ste11 gene, which encodes a key transcription factor for sexual development, was greatly reduced in the disruptant, and overexpression of ste11+ suppressed the deficiency of the pcr1 disruptant in sexual development. It has been shown that expression of ste11 is negatively regulated by cyclic AMP-dependent protein kinase (PKA) and that the loss of PKA activity results in ectopic sexual development. Disruption of pcr1 blocked ectopic sexual development. Furthermore, disruption of pcr1 reduced expression of fbp1, a glucose-repressible gene negatively regulated by PKA. These results suggest that Pcr1 is a putative transcriptional regulator whose activity may be controlled by PKA. Alternatively, its activity may be independent of PKA, and full induction of ste11 and fbp1 expression requires the function of Pcr1 in addition to elimination of the repression by PKA.

Cloning of a Calmodulin Kinase I Homologue fromSchizosaccharomyces pombe

“…Recent studies have indicated the presence of homologues of the transcription factors known to be CaMK-I substrates in mammalian cells (e.g. ATF1, CREB) (41)(42)(43)(44). Whether or not these are substrates for S. pombe CMK1 either in vitro or in vivo will be the subject of future studies.…”

Protein Phosphatase 2C Acts Independently of Stress-activated Kinase Cascade to Regulate the Stress Response in Fission Yeast

“…This observation suggests that Ptc1 may indirectly regulate Atf1, perhaps by dephosphorylating an Atf1 co-factor involved in transcriptional induction. It was recently shown that Atf1 forms heterodimers with the protein encoded by the pcr1 ϩ gene (28). ⌬pcr1 cells display a phenotype similar to ⌬atf1 mutant cells, suggesting that Atf1-Pcr1 heterodimers may have an important role in the stress-induced gene transcription.…”

SAPKs and transcription factors do the nucleocytoplasmic tango: Figure 1.

“…This is not an unreasonable notion as c-Jun can recruit JNK to phosphorylate dimerization partners via specific docking interactions (Kallunki et al1996). At least three ATF family members have been identified in fission yeast in addition to Atf1, namely Pcr1, Atf21, and Cbp1 (Takeda et al 1995;Kanoh et al 1996;Shiozaki and Russell 1996;Watanabe and Yamamoto 1996;J.B.A. Millar and N. Jones, unpubl.…”