CpG distribution and methylation pattern in porcine parvovirus

PLoS One. 2013 Dec 31;8(12):e85986. doi: 10.1371/journal.pone.0085986. eCollection 2013.

Abstract

Based on GC content and the observed/expected CpG ratio (oCpGr), we found three major groups among the members of subfamily Parvovirinae: Group I parvoviruses with low GC content and low oCpGr values, Group II with low GC content and high oCpGr values and Group III with high GC content and high oCpGr values. Porcine parvovirus belongs to Group I and it features an ascendant CpG distribution by position in its coding regions similarly to the majority of the parvoviruses. The entire PPV genome remains hypomethylated during the viral lifecycle independently from the tissue of origin. In vitro CpG methylation of the genome has a modest inhibitory effect on PPV replication. The in vitro hypermethylation disappears from the replicating PPV genome suggesting that beside the maintenance DNMT1 the de novo DNMT3a and DNMT3b DNA methyltransferases can't methylate replicating PPV DNA effectively either, despite that the PPV infection does not seem to influence the expression, translation or localization of the DNA methylases. SNP analysis revealed high mutability of the CpG sites in the PPV genome, while introduction of 29 extra CpG sites into the genome has no significant biological effects on PPV replication in vitro. These experiments raise the possibility that beyond natural selection mutational pressure may also significantly contribute to the low level of the CpG sites in the PPV genome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Composition
  • Computational Biology*
  • CpG Islands*
  • DNA (Cytosine-5-)-Methyltransferases / metabolism
  • DNA Methylation*
  • Evolution, Molecular
  • Genome, Viral / genetics
  • Parvovirus, Porcine / genetics*
  • Parvovirus, Porcine / physiology
  • Protein Biosynthesis
  • Transcription, Genetic
  • Virus Replication

Substances

  • DNA (Cytosine-5-)-Methyltransferases

Grants and funding

This work was supported by OTKA and NKTH (Mobilitás 08-C OTKA 81187), the János Bolyai Fellowship from the Hungarian Academy of Sciences (BO/00414/10). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.