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The human REV1 gene codes for a DNA template-dependent dCMP transferase
1Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536, USA.
Nucleic Acids Research
|October 28, 1999
Summary
Human REV1 protein acts as a DNA polymerase, inserting nucleotides opposite DNA damage. This enzyme is crucial for mutagenic translesion DNA synthesis, particularly bypassing apurinic/apyrimidinic sites in human cells.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- DNA damage is a significant cause of mutations during cellular replication.
- The Rev1 protein is essential for the DNA damage-induced mutagenesis pathway in yeast (Saccharomyces cerevisiae).
Purpose of the Study:
- To isolate and characterize the human homolog of the yeast REV1 gene.
- To elucidate the enzymatic activity and potential role of the human REV1 protein in DNA repair and mutagenesis.
Main Methods:
- Isolation of human cDNA homologous to yeast REV1.
- Sequence analysis to determine protein size and molecular weight.
- Biochemical assays to assess DNA polymerase activity, specifically dCMP insertion opposite various DNA templates.
Main Results:
- Human REV1 cDNA (4255 bp) encodes a 1251-amino acid protein (138,248 Da).
- Human REV1 protein functions as a deoxycytidine monophosphate (dCMP) transferase, inserting dCMP opposite template guanine (G).
- The enzyme efficiently inserts dCMP opposite DNA template apurinic/apyrimidinic (AP) sites and uracil residues, suggesting a role in bypassing DNA lesions.
Conclusions:
- Human REV1 protein is a dCMP transferase involved in mutagenic translesion DNA synthesis.
- It plays a critical role in bypassing template AP sites during DNA replication in human cells.
- The ubiquitous expression of the REV1 gene indicates its fundamental importance across human tissues.