Murine DNA polymerase.alpha-primase initiates RNA-primed DNA synthesis preferentially upstream of a 3'-CC(C/A)-5' motif.
1990; Elsevier BV; Volume: 265; Issue: 7 Linguagem: Inglês
10.1016/s0021-9258(19)39635-8
ISSN1083-351X
AutoresScott Davey, Emanuel A. Faust,
Tópico(s)RNA and protein synthesis mechanisms
ResumoWe find that the purified murine DNA polymerase.alpha-primase complex exhibits the greatest affinity for DNA templates in which CCC occurs 10 nucleotides downstream of a DNA primase initiation site (Km = 6.6 +/- 0.3 pM). Templates with 3'-CCA-5' at this position are less efficiently utilized (Km = 16 +/- 4 pM). Point mutations that disrupt the 3'-CC(C/A)-5' motif further decrease the affinity for DNA approximately 7-fold (Km = 105 +/- 58 pM). Mutations at the primase start site reduce Vmax 2-fold. Template pyrimidines are required for priming, and initiation with ATP is preferred to initiation with GTP. We conclude that a component of the DNA polymerase.alpha-primase complex recognizes a 3'-CC(C/A)-5' motif in the DNA template, downstream of a primase start site, and that this interaction controls site selection and frequency of initiation by DNA primase.
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