Yeast open reading frame YCR14C encodes a DNA β-polymerase-like enzyme

Rajendra Prasad, Steven G. Widen, Rakesh K. Singhal, John Watkins, Louise Prakash, Samuel H. Wilson

Research output: Contribution to journalArticle

71 Scopus citations

Abstract

We have shown by activity gel that overexpression in E.coli of a yeast chromosome 3 open reading frame (ORF) designated YCR14C and bearing homology to mammalian DNA polymeraseβ results in a new DNA polymerase in the host cells. The molecular mass of this enzyme corresponded to the YCR14C-predicted 67 kDa protein, and NH2-terminal amino acid sequencing confirmed that the expressed protein was encoded by the yeast ORF. This new yeast DNA polymerase was purified to homogeneity from E.coli. In a fashion similar to that of mammalian β-polymerases, the purified yeast enzyme exhibited distributive DNA synthesis on DNA substrate with a single-stranded template and processive gap-filling synthesis on a short-gapped DNA substrate. Activity of this yeast β-polymerase-like enzyme was sensitive to the β-polymerase inhibitor ddNTP and resistant to both 1 mM NEM and neutralizing antibody to E.coli DNA polymerase I. These results, therefore, indicate that YCR14C encodes a DNA β- polymerase-like enzyme in yeast, and we name it DNA polymerase IV. Yeast strains harboring a deletion mutation of the pol IV gene are viable, they exhibit no increase in sensitivity to ultraviolet light, ionizing radiation or alkylating agents, and sporulation and spore viability are not affected in the mutant.

Original languageEnglish (US)
Pages (from-to)5301-5307
Number of pages7
JournalNucleic acids research
Volume21
Issue number23
DOIs
StatePublished - Nov 25 1993

ASJC Scopus subject areas

  • Genetics

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