Title

Molecular mechanism of recombination in herpes simplex virus type-1

Date of Award

2003

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

First Committee Member

Paul E. Boehmer, Committee Chair

Abstract

Herpes simplex virus type-1 is a large double-strand DNA virus with the distinguishing ability to establish latent, life-long infections. Its widespread prevalence amongst human population, its ability to spread an asymptomatic epidemic and the lack of an effective vaccine makes the virus clinically significant. Upon entering the host cell, the virus executes an intricate chain of events geared towards optimizing its replication. This sets an interesting paradigm to study cellular mechanisms. A salient feature of herpesvirus is its ability to recombine at a high frequency. Work done towards the fulfillment of this thesis sheds light on the mechanism of viral recombination. ICP8, the virus encoded single-strand DNA-binding protein, in conjunction with the virus encoded helicase-primase, was shown to promote a classical recombination reaction called strand exchange. The concerted action of the two proteins was shown to efficiently transfer the homologous strand of a duplex DNA onto a circular single-stranded DNA molecule. ICP8 was also demonstrated to promote strand invasion, another prototypical reaction catalyzed by recombinases. The protein does so by promoting the assimilation of a single-stranded DNA molecule into a homologous supercoiled DNA plasmid. In addition, strand exchange as well as strand invasion products were shown to provide primers for DNA synthesis by the virus-encoded polymerase. Thus, the data generated in this thesis demonstrates that the viral encoded proteins are capable of performing recombination reactions in the absence RecA-like protein. Furthermore, the recombination products nucleate the assembly of a replisome thereby demonstrating a direct coupling between recombination and replication. The data attests the hypothesis that branched intermediates are generated due to recombination-dependent replication. This interplay between recombination and replication may contribute towards maintaining viral genomic stability by rescuing stalled replication forks and repairing DNA strand breaks.

Keywords

Biology, Molecular

Link to Full Text

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