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Genomic sequencing reveals absence of DNA methylation in the major late promoter of adenovirus type 2 DNA in the virion and in productively infected cells
Author(s) -
Kämmer Christina,
Doerfler Walter
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00248-8
Subject(s) - biology , dna methylation , microbiology and biotechnology , dna , dna nanoball sequencing , methylated dna immunoprecipitation , dna sequencing , genomic dna , rna directed dna methylation , chloramphenicol acetyltransferase , methylation , genetics , gene , genomic library , promoter , gene expression , base sequence
By using methylation‐sensitive restriction endonucleases, we have previously provided evidence that adenovirus type 2 (Ad2) virion DNA or free intranuclear Ad2 DNA in productively infected hamster or human cells is not methylated. We have now chosen a different experimental approach and have investigated the major late promoter (MLP) sequence of Ad2 DNA for the presence of 5‐methyldeoxycytidine (5‐mC) residues with the genomic sequencing technique. This study has been prompted by the finding that the MLP of Ad2 DNA can be inactivated by sequence‐specific methylation in experiments in which a MLP‐chloramphenicol acetyltransferase construct has been transcribed in a cell‐free system from HeLa cell nuclear extracts. Virion Ad2 DNA and Ad2 DNA isolated from productively infected human or hamster cells between 1 and 48 h post‐infection (p.i.) have now been analyzed. There is no evidence for the presence of 5‐mC in the cytidine positions in the MLP of any of these Ad2 preparations. We conclude that DNA methylation does not seem to play a role in the early‐late control of this viral promoter. The sensitivity of the genomic sequencing technique does not permit us to exclude the unlikely presence of 5‐mC in a few Ad2 DNA molecules.