DNA Polymerases that Propagate the Eukaryotic DNA Replication Fork

Authors: Garg, Parie; Burgers, Peter

Source: Critical Reviews in Biochemistry and Molecular Biology, Volume 40, Number 2, March-April 2005 , pp. 115-128(14)

Publisher: Informa Healthcare

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Abstract:

Three DNA polymerases are thought to function at the eukaryotic DNA replication fork. Currently, a coherent model has been derived for the composition and activities of the lagging strand machinery. RNA-DNA primers are initiated by DNA polymerase a -primase. Loading of the proliferating cell nuclear antigen, PCNA, dissociates DNA polymerase a and recruits DNA polymerase d and the flap endonuclease FEN1 for elongation and in preparation for its requirement during maturation, respectively. Nick translation by the strand displacement action of DNA polymerase d, coupled with the nuclease action of FEN1, results in processive RNA degradation until a proper DNA nick is reached for closure by DNA ligase I. In the event of excessive strand displacement synthesis, other factors, such as the Dna2 nuclease/helicase, are required to trim excess flaps. Paradoxically, the composition and activity of the much simpler leading strand machinery has not been clearly established. The burden of evidence suggests that DNA polymerase e normally replicates this strand, but under conditions of dysfunction, DNA polymerase d may substitute.

Keywords: replication fork; DNA polymerase; DNA replication; Okazaki fragment; nuclease; PCNA; FEN1

Document Type: Research article

DOI: http://dx.doi.org/10.1080/10409230590935433

Affiliations: 1: Washington University School of Medicine, St. Louis, MO, USA

Publication date: 2005-03-01

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