The chromatin remodeling factor SMARCB1 forms a complex with human cytomegalovirus proteins UL114 and UL44.

Toril Ranneberg-Nilsen,Ragnhild Slettebakk,Halvor Rollag,Magnar Bjørås,Paul Hoff Backe,Øyvind Olsen,Luisa Luna

doi:10.1371/journal.pone.0034119

Toril Ranneberg-Nilsen, Ragnhild Slettebakk + Show 5 more

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https://doi.org/10.1371/journal.pone.0034119

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Journal: PloS one	Publication Date: Mar 27, 2012
Citations: 72	License type: CC BY 4.0

Affiliation: Oslo University Hospital, University of Oslo

Abstract

BackgroundHuman cytomegalovirus (HCMV) uracil DNA glycosylase, UL114, is required for efficient viral DNA replication. Presumably, UL114 functions as a structural partner to other factors of the DNA-replication machinery and not as a DNA repair protein. UL114 binds UL44 (HCMV processivity factor) and UL54 (HCMV-DNA-polymerase). In the present study we have searched for cellular partners of UL114.Methodology/Principal FindingsIn a yeast two-hybrid screen SMARCB1, a factor of the SWI/SNF chromatin remodeling complex, was found to be an interacting partner of UL114. This interaction was confirmed in vitro by co-immunoprecipitation and pull-down. Immunofluorescence microscopy revealed that SMARCB1 along with BRG-1, BAF170 and BAF155, which are the core SWI/SNF components required for efficient chromatin remodeling, were present in virus replication foci 24–48 hours post infection (hpi). Furthermore a direct interaction was also demonstrated for SMARCB1 and UL44.Conclusions/SignificanceThe core SWI/SNF factors required for efficient chromatin remodeling are present in the HCMV replication foci throughout infection. The proteins UL44 and UL114 interact with SMARCB1 and may participate in the recruitment of the SWI/SNF complex to the chromatinized virus DNA. Thus, the presence of the SWI/SNF chromatin remodeling complex in replication foci and its association with UL114 and with UL44 might imply its involvement in different DNA transactions.

Highlights

The human cytomegalovirus (HCMV), a member of the Betaherpesviridae, is an important human pathogen
To identify cellular partners of the HCMV encoded uracil DNA glycosylase, UL114, we used a yeast based two-hybrid system with a ‘‘bait’’ plasmid encoding the full-length UL114 protein fused to GAL4 DNA-binding domain (BD) in pGBKT7 transformed into the yeast strain AH109
The two-hybrid screen was performed by mating a yeast strain Y187 pre-transformed with a highly complex brain cDNA library cloned into the yeast GAL4 activation domain (AD) vector pACT2 with AH109-pGBKT7UL114

Summary

Introduction

The human cytomegalovirus (HCMV), a member of the Betaherpesviridae, is an important human pathogen. The HCMV genomes serve as templates for transcription and replication, thought to take place within discrete nuclear inclusions. These inclusions develop adjacent to small sites known as promyelocytic leukemia bodies or nuclear domain 10 and take over large parts of the nuclear space at late times post infection [10,11]. Human cytomegalovirus (HCMV) uracil DNA glycosylase, UL114, is required for efficient viral DNA replication. In the present study we have searched for cellular partners of UL114

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