Characterization of the POL3 gene product from Schizosaccharomyces pombe indicates inter-species conservation of the catalytic subunit of DNA polymerase delta.
The Schizosaccharomyces pombe POL3 gene was isolated by sequence homology with a region of the Saccharomyces cerevisiae POL3 gene, the only gene sequenced to date encoding the catalytic subunit of eukaryotic DNA polymerase delta. The fission yeast POL3 gene contains a 52 base-pair (bp) intron and encodes a 3600 bp transcript the 5'-end of which is located 32 bp upstream from the initiation codon. The polypeptides predicted from budding and fission yeast POL3 genes share 52% of conserved amino acid residues and have a 60% identical central region. This structural conservation of the catalytic subunit of DNA polymerases delta is probably related to functional constraints. A portion of the most conserved region was used to raise antibodies against an S. pombe polymerase delta/beta-galactosidase fusion protein expressed in Escherichia coli. The purified antibodies recognized a 123,000 Da protein in S. pombe wild-type cell extracts and inhibited an aphidicolin-sensitive DNA polymerase activity that was distinct from DNA polymerase alpha. The antibodies also detected a 140,000 Da protein in extracts from different proliferating mammalian cells, indicating that the catalytic subunits of DNA polymerase delta are highly conserved between yeast and higher eukaryotes.
Pignède
G
G
Laboratoire de Biologie Moléculaire de la Réplication UPR 272 IRSC-CNRS, Villejuif, France.
Bouvier
D
D
de Recondo
A M
AM
Baldacci
G
G
D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003429:Cross Reactions; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase / Q000235:genetics* / Q000276:immunology; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D012331:RNA, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics*; D016415:Sequence Alignment; D014158:Transcription, Genetic
D012331:RNA, Fungal; D012333:RNA, Messenger; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase