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Directed Nucleosome Sliding during the Formation of the Simian Virus 40 Particle Exposes DNA Sequences Required for Early Transcription
- Source :
- Journal of Virology. 93
- Publication Year :
- 2019
- Publisher :
- American Society for Microbiology, 2019.
-
Abstract
- Simian virus 40 (SV40) exists as chromatin throughout its life cycle and undergoes typical epigenetic regulation mediated by changes in nucleosome location and associated histone modifications. In order to investigate the role of epigenetic regulation during the encapsidation of late-stage minichromosomes into virions, we mapped the locations of nucleosomes containing acetylated or methylated lysines in the histone tails of H3 and H4 present in the chromatin from 48-h-postinfection minichromosomes and disrupted virions. In minichromosomes obtained late in infection, nucleosomes were found carrying various histone modifications primarily in the regulatory region, with a major nucleosome located within the enhancer and other nucleosomes at the early and late transcriptional start sites. The nucleosome found in the enhancer would be expected to repress early transcription by blocking access to part of the SP1 binding sites and the left side of the enhancer in late-stage minichromosomes while also allowing late transcription. In chromatin from virions, the principal nucleosome located in the enhancer was shifted ∼70 bases in the late direction from what was found in minichromosomes, and the level of modified histones was increased throughout the genome. The shifting of the enhancer-associated nucleosome to the late side would effectively serve as a switch to relieve the repression of early transcription found in late minichromosomes while likely also repressing late transcription by blocking access to necessary regulatory sequences. This epigenetic switch appeared to occur during the final stage of virion formation. IMPORTANCE For a virus to complete infection, it must produce a new virus particle in which the genome is able to support a new infection. This is particularly important for viruses like simian virus 40 (SV40), which exist as chromatin throughout their life cycles, since chromatin structure plays a major role in the regulation of the life cycle. In order to determine the role of SV40 chromatin structure late in infection, we mapped the locations of nucleosomes and their histone tail modifications in SV40 minichromosomes and in the SV40 chromatin found in virions using chromatin immunoprecipitation-DNA sequencing (ChIP-Seq). We have identified a novel viral transcriptional control mechanism in which a nucleosome found in the regulatory region of the SV40 minichromosome is directed to slide during the formation of the virus particle, exposing transcription factor binding sites required for early transcription that were previously blocked by the presence of the nucleosome.
- Subjects :
- Transcription, Genetic
viruses
Immunology
Simian virus 40
Biology
Virus Replication
Microbiology
Cell Line
Epigenesis, Genetic
Histones
03 medical and health sciences
0302 clinical medicine
Minichromosome
Virology
Chlorocebus aethiops
Transcriptional regulation
Animals
Nucleosome
Epigenetics
Enhancer
030304 developmental biology
0303 health sciences
Binding Sites
Base Sequence
Virion
Acetylation
Chromatin Assembly and Disassembly
Chromatin
Nucleosomes
Genome Replication and Regulation of Viral Gene Expression
Cell biology
DNA binding site
Histone
030220 oncology & carcinogenesis
Insect Science
DNA, Viral
biology.protein
Protein Processing, Post-Translational
Subjects
Details
- ISSN :
- 10985514 and 0022538X
- Volume :
- 93
- Database :
- OpenAIRE
- Journal :
- Journal of Virology
- Accession number :
- edsair.doi.dedup.....cbcda05e53050daf66fd4cc6b65fd080