The CDC13-STN1-TEN1 complex stimulates Pol α activity by promoting RNA priming and primase-to-polymerase switch

Nat Commun. 2014 Dec 12;5:5762. doi: 10.1038/ncomms6762.

Abstract

Emerging evidence suggests that Cdc13-Stn1-Ten1 (CST), an RPA-like ssDNA-binding complex, may regulate primase-Pol α (PP) activity at telomeres constitutively, and at other genomic locations under conditions of replication stress. Here we examine the mechanisms of PP stimulation by CST using purified complexes derived from Candida glabrata. While CST does not enhance isolated DNA polymerase activity, it substantially augments both primase activity and primase-to-polymerase switching. CST also simultaneously shortens the RNA and lengthens the DNA in the chimeric products. Stn1, the most conserved subunit of CST, is alone capable of PP stimulation. Both the N-terminal OB fold and the C-terminal winged-helix domains of Stn1 can bind to the Pol12 subunit of the PP complex and stimulate PP activity. Our findings provide mechanistic insights on a well-conserved pathway of PP regulation that is critical for genome stability.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Binding Sites
  • Candida glabrata / genetics*
  • Candida glabrata / metabolism
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism
  • DNA Polymerase I / genetics
  • DNA Polymerase I / metabolism*
  • DNA Primase / genetics
  • DNA Primase / metabolism*
  • DNA, Fungal / genetics
  • DNA, Fungal / metabolism
  • DNA, Single-Stranded / genetics
  • DNA, Single-Stranded / metabolism
  • Fungal Proteins / chemistry*
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Gene Expression Regulation, Fungal*
  • Genome, Fungal
  • Genomic Instability
  • Protein Binding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • RNA, Fungal / genetics
  • RNA, Fungal / metabolism
  • Telomere / chemistry*
  • Telomere / metabolism
  • Telomere-Binding Proteins / chemistry*
  • Telomere-Binding Proteins / genetics
  • Telomere-Binding Proteins / metabolism

Substances

  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • DNA, Fungal
  • DNA, Single-Stranded
  • Fungal Proteins
  • RNA, Fungal
  • Telomere-Binding Proteins
  • DNA Primase
  • DNA Polymerase I