A dimeric Rep protein initiates replication of a linear archaeal virus genome: implications for the Rep mechanism and viral replication

TY - JOUR

T1 - A dimeric Rep protein initiates replication of a linear archaeal virus genome: implications for the Rep mechanism and viral replication

AU - Oke, Muse

AU - Kerou, Melina

AU - Liu, Huanting

AU - Peng, Xu

AU - Garrett, Roger Antony

AU - Prangishvili, David

AU - Naismith, James H

AU - White, Malcolm F

PY - 2011/1

Y1 - 2011/1

N2 - The Rudiviridae are a family of rod-shaped archaeal viruses with covalently closed, linear double-stranded DNA (dsDNA) genomes. Their replication mechanisms remain obscure, although parallels have been drawn to the Poxviridae and other large cytoplasmic eukaryotic viruses. Here we report that a protein encoded in the 34-kbp genome of the rudivirus SIRV1 is a member of the replication initiator (Rep) superfamily of proteins, which initiate rolling-circle replication (RCR) of diverse viruses and plasmids. We show that SIRV Rep nicks the viral hairpin terminus, forming a covalent adduct between an active-site tyrosine and the 5' end of the DNA, releasing a 3' DNA end as a primer for DNA synthesis. The enzyme can also catalyze the joining reaction that is necessary to reseal the DNA hairpin and terminate replication. The dimeric structure points to a simple mechanism through which two closely positioned active sites, each with a single tyrosine residue, work in tandem to catalyze DNA nicking and joining. We propose a novel mechanism for rudivirus DNA replication, incorporating the first known example of a Rep protein that is not linked to RCR. The implications for Rep protein function and viral replication are discussed.

AB - The Rudiviridae are a family of rod-shaped archaeal viruses with covalently closed, linear double-stranded DNA (dsDNA) genomes. Their replication mechanisms remain obscure, although parallels have been drawn to the Poxviridae and other large cytoplasmic eukaryotic viruses. Here we report that a protein encoded in the 34-kbp genome of the rudivirus SIRV1 is a member of the replication initiator (Rep) superfamily of proteins, which initiate rolling-circle replication (RCR) of diverse viruses and plasmids. We show that SIRV Rep nicks the viral hairpin terminus, forming a covalent adduct between an active-site tyrosine and the 5' end of the DNA, releasing a 3' DNA end as a primer for DNA synthesis. The enzyme can also catalyze the joining reaction that is necessary to reseal the DNA hairpin and terminate replication. The dimeric structure points to a simple mechanism through which two closely positioned active sites, each with a single tyrosine residue, work in tandem to catalyze DNA nicking and joining. We propose a novel mechanism for rudivirus DNA replication, incorporating the first known example of a Rep protein that is not linked to RCR. The implications for Rep protein function and viral replication are discussed.

KW - DNA Helicases

KW - DNA, Viral

KW - Models, Biological

KW - Protein Multimerization

KW - Rudiviridae

KW - Trans-Activators

KW - Viral Proteins

KW - Virus Replication

U2 - 10.1128/JVI.01467-10

DO - 10.1128/JVI.01467-10

M3 - Journal article

C2 - 21068244

SN - 0022-538X

VL - 85

SP - 925

EP - 931

JO - Journal of Virology

JF - Journal of Virology

IS - 2

ER -