scholarly journals Purification of Host Cell Enzymes Involved in Adeno-Associated Virus DNA Replication

2007 ◽  
Vol 81 (11) ◽  
pp. 5777-5787 ◽  
Author(s):  
Kevin Nash ◽  
Weijun Chen ◽  
William F. McDonald ◽  
Xiaohuai Zhou ◽  
Nicholas Muzyczka
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Dna Helicase ◽  
Strand Displacement ◽  
Adeno Associated Virus ◽  
Replication System ◽  
Factor C

ABSTRACT Adeno-associated virus (AAV) replicates its DNA by a modified rolling-circle mechanism that exclusively uses leading strand displacement synthesis. To identify the enzymes directly involved in AAV DNA replication, we fractionated adenovirus-infected crude extracts and tested them in an in vitro replication system that required the presence of the AAV-encoded Rep protein and the AAV origins of DNA replication, thus faithfully reproducing in vivo viral DNA replication. Fractions that contained replication factor C (RFC) and proliferating cell nuclear antigen (PCNA) were found to be essential for reconstituting AAV DNA replication. These could be replaced by purified PCNA and RFC to retain full activity. We also found that fractions containing polymerase δ, but not polymerase ε or α, were capable of replicating AAV DNA in vitro. This was confirmed when highly purified polymerase δ complex purified from baculovirus expression clones was used. Curiously, as the components of the DNA replication system were purified, neither the cellular single-stranded DNA binding protein (RPA) nor the adenovirus-encoded DNA binding protein was found to be essential for DNA replication; both only modestly stimulated DNA synthesis on an AAV template. Also, in addition to polymerase δ, RFC, and PCNA, an as yet unidentified factor(s) is required for AAV DNA replication, which appeared to be enriched in adenovirus-infected cells. Finally, the absence of any apparent cellular DNA helicase requirement led us to develop an artificial AAV replication system in which polymerase δ, RFC, and PCNA were replaced with T4 DNA polymerase and gp32 protein. This system was capable of supporting AAV DNA replication, demonstrating that under some conditions the Rep helicase activity can function to unwind duplex DNA during strand displacement synthesis.

scholarly journals Role of the Adenovirus DNA-Binding Protein in In Vitro Adeno-Associated Virus DNA Replication

1998 ◽  
Vol 72 (1) ◽  
pp. 420-427 ◽  
Author(s):  
Peter Ward ◽  
Frank B. Dean ◽  
Michael E. O’Donnell ◽  
Kenneth I. Berns
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Basic Question ◽  
Adeno Associated Virus ◽  
Vitro Assay ◽  
Cell Extracts ◽  
Vector Sequences

ABSTRACT A basic question in adeno-associated virus (AAV) biology has been whether adenovirus (Ad) infection provided any function which directly promoted replication of AAV DNA. Previously in vitro assays for AAV DNA replication, using linear duplex AAV DNA as the template, uninfected or Ad-infected HeLa cell extracts, and exogenous AAV Rep protein, demonstrated that Ad infection provides a direct helper effect for AAV DNA replication. It was shown that the nature of this helper effect was to increase the processivity of AAV DNA replication. Left unanswered was the question of whether this effect was the result of cellular factors whose activity was enhanced by Ad infection or was the result of direct participation of Ad proteins in AAV DNA replication. In this report, we show that in the in vitro assay, enhancement of processivity occurs with the addition of either the Ad DNA-binding protein (Ad-DBP) or the human single-stranded DNA-binding protein (replication protein A [RPA]). Clearly Ad-DBP is present after Ad infection but not before, whereas the cellular level of RPA is not apparently affected by Ad infection. However, we have not measured possible modifications of RPA which might occur after Ad infection and affect AAV DNA replication. When the substrate for replication was an AAV genome inserted into a plasmid vector, RPA was not an effective substitute for Ad-DBP. Extracts supplemented with Ad-DBP preferentially replicated AAV sequences rather than adjacent vector sequences; in contrast, extracts supplemented with RPA preferentially replicated vector sequences.

scholarly journals Studies of the Silencing of Baculovirus DNA Binding Protein

2007 ◽  
Vol 81 (11) ◽  
pp. 6122-6127 ◽  
Author(s):  
Ilja Quadt ◽  
Jan W. M. van Lent ◽  
Dagmar Knebel-Mörsdorf
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Primary Role ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Expression Of Genes ◽  
Replication Sites

ABSTRACT Baculovirus DNA binding protein (DBP) binds preferentially single-stranded DNA in vitro and colocalizes with viral DNA replication sites. Here, its putative role as viral replication factor has been addressed by RNA interference. Silencing of DBP in Autographa californica multiple nucleopolyhedrovirus-infected cells increased expression of LEF-3, LEF-4, and P35. In contrast, expression of the structural genes coding for P39 and polyhedrin was suppressed while expression of genes coding for P10 and GP64 was unaffected. In the absence of DBP, viral DNA replication sites were formed, indicating replication of viral DNA. Electron microscopy studies, however, revealed a loss of formation of polyhedra and virus envelopment, suggesting that the primary role of DBP is viral formation rather than viral DNA replication.

scholarly journals In Vivo Occupancy of Mitochondrial Single-Stranded DNA Binding Protein Supports the Strand Displacement Mode of DNA Replication

PLoS Genetics ◽  
2014 ◽  
Vol 10 (12) ◽  
pp. e1004832 ◽  
Author(s):  
Javier Miralles Fusté ◽  
Yonghong Shi ◽  
Sjoerd Wanrooij ◽  
Xuefeng Zhu ◽  
Elisabeth Jemt ◽  
...  
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Strand Displacement ◽  
Single Stranded Dna ◽  
Displacement Mode

A cleavage product of the adenovirus DNA binding protein is active in DNA replication in vitro

Virology ◽  
1980 ◽  
Vol 101 (1) ◽  
pp. 307-310 ◽  
Author(s):  
Hiroyoshi Ariga ◽  
Hannah Klein ◽  
Arnold J. Levine ◽  
Marshall S. Horwitz
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Cleavage Product

scholarly journals The DNA-binding protein HTa from Thermoplasma acidophilum is an archaeal histone analog

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Antoine Hocher ◽  
Maria Rojec ◽  
Jacob B Swadling ◽  
Alexander Esin ◽  
Tobias Warnecke
Keyword(s):  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Coli Strain ◽  
Micrococcal Nuclease ◽  
Thermoplasma Acidophilum ◽  
Chromatin Architecture ◽  
Archaeal Histone

Histones are a principal constituent of chromatin in eukaryotes and fundamental to our understanding of eukaryotic gene regulation. In archaea, histones are widespread but not universal: several lineages have lost histone genes. What prompted or facilitated these losses and how archaea without histones organize their chromatin remains largely unknown. Here, we elucidate primary chromatin architecture in an archaeon without histones, Thermoplasma acidophilum, which harbors a HU family protein (HTa) that protects part of the genome from micrococcal nuclease digestion. Charting HTa-based chromatin architecture in vitro, in vivo and in an HTa-expressing E. coli strain, we present evidence that HTa is an archaeal histone analog. HTa preferentially binds to GC-rich sequences, exhibits invariant positioning throughout the growth cycle, and shows archaeal histone-like oligomerization behavior. Our results suggest that HTa, a DNA-binding protein of bacterial origin, has converged onto an architectural role filled by histones in other archaea.

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