Cloning of the pka1 gene encoding the catalytic subunit of the cAMP-dependent protein kinase in Schizosaccharomyces pombe.
We have isolated Schizosaccharomyces pombe genes that confer sterility to the fission yeast cell when expressed from a multicopy plasmid. One of these genes strongly hybridized to a probe carrying the open reading frame of Saccharomyces cerevisiae TPK1, which encodes a catalytic subunit of the cAMP-dependent protein kinase (protein kinase A). This S. pombe gene, named pka1, has a coding potential of 512 amino acids, and the deduced gene product is 60% identical with the S. cerevisiae Tpk1 protein in the C-terminal 320 amino acids. Disruption of pka1 slows cell growth but is not lethal. The resultant cells, however, are highly derepressed for sexual development, readily undergoing conjugation and sporulation in the absence of nitrogen starvation. They are, thus, phenotypically indistinguishable from the adenylyl cyclase-defective (cyr1-) cells previously characterized, except that the pka1- spores are retarded in germination, whereas the cyr1- spores are not. Disruption of pka1 is epistatic to a defect in cgs1, which encodes the regulatory subunit of protein kinase A. These results strongly suggest that the product of pka1 is a catalytic subunit of protein kinase A and, furthermore, that S. pombe has only one gene encoding it. This situation contrasts with the case of S. cerevisiae, in which three genes encode the catalytic subunits.
Maeda
T
T
Department of Biophysics and Biochemistry, School of Science, University of Tokyo, Japan.
Watanabe
Y
Y
Kunitomo
H
H
Yamamoto
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D017124:Conserved Sequence; D017868:Cyclic AMP-Dependent Protein Kinases / Q000096:biosynthesis / Q000235:genetics*; D004271:DNA, Fungal / Q000032:analysis; D004330:Drosophila / Q000201:enzymology / Q000235:genetics; D005800:Genes, Fungal; D007246:Infertility; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016366:Open Reading Frames; D010957:Plasmids; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000235:genetics* / Q000502:physiology; D017386:Sequence Homology, Amino Acid
D004271:DNA, Fungal; D046911:Macromolecular Substances; D017868:Cyclic AMP-Dependent Protein Kinases