Promoter dependent RNA polymerase II bypass of the epimerizable DNA lesion, Fapyâ¢dG and 8-Oxo-2'-deoxyguanosine.
Nucleic Acids Res
; 52(13): 7437-7446, 2024 Jul 22.
Article
in En
| MEDLINE
| ID: mdl-38908029
ABSTRACT
Formamidopyrimidine (Fapyâ¢dG) is a major lesion arising from oxidation of dG that is produced from a common chemical precursor of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OxodGuo). In human cells, replication of single-stranded shuttle vectors containing Fapyâ¢dG is more mutagenic than 8-OxodGuo. Here, we present the first data regarding promoter dependent RNA polymerase II bypass of Fapyâ¢dG. 8-OxodGuo bypass was examined side-by-side. Experiments were carried out using double-stranded shuttle vectors in HeLa cell nuclear lysates and in HEK 293T cells. The lesions do not significantly block transcriptional bypass efficiency. Less than 2% adenosine incorporation occurred in cells when the lesions were base paired with dC. Inhibiting base excision repair in HEK 293T cells significantly increased adenosine incorporation, particularly from Fapyâ¢dGdC bypass which yielded â¼25% adenosine incorporation. No effect was detected upon transcriptional bypass of either lesion in nucleotide excision repair deficient cells. Transcriptional mutagenesis was significantly higher when shuttle vectors containing dA opposite one of the lesions were employed. For Fapyâ¢dGdA bypass, adenosine incorporation was greater than 85%; whereas 8-OxodGuodA yielded >20% point mutations. The combination of more frequent replication mistakes and greater error-prone Pol II bypass suggest that Fapyâ¢dG is more mutagenic than 8-OxodGuo.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
DNA Damage
/
RNA Polymerase II
/
Promoter Regions, Genetic
/
Deoxyguanosine
/
8-Hydroxy-2'-Deoxyguanosine
Limits:
Humans
Language:
En
Journal:
Nucleic Acids Res
Year:
2024
Document type:
Article
Affiliation country: