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Forward mutation rate of human immunodeficiency virus type 1 in a T lymphoid cell line
1McArdle Laboratory for Cancer Research, University of Wisconsin Medical School, Madison 53706, USA.
Insights
The human immunodeficiency virus type 1 (HIV-1) mutation rate is similar in HeLa and CEM-A cells. This finding indicates comparable accuracy in HIV-1 reverse transcription across different cell types.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- An established in vivo assay detects forward mutations in human immunodeficiency virus type 1 (HIV-1) within a single replication cycle.
- The lacZalpha peptide gene serves as a reporter for mutations, enabling determination of mutation rates and types.
Purpose of the Study:
- To assess if cell type influences the mutation rate of HIV-1.
- To compare the HIV-1 mutation rate in HeLa cells with that in CEM-A cells, a T lymphoid cell line.
Main Methods:
- Utilized an in vivo assay for detecting forward mutations in HIV-1.
- Quantified HIV-1 mutation rates per target base pair per replication cycle in both HeLa and CEM-A cell lines.
- Characterized the types and numbers of mutations observed.
Main Results:
- The forward mutation rate for HIV-1 in HeLa cells was 3 x 10(-5) mutations per target base pair per cycle.
- The mutation rate for HIV-1 reverse transcription in CEM-A cells was 4 x 10(-5) mutations per target base pair per cycle.
- Base substitution mutations predominated, with G-to-A transitions being the most frequent. G-to-A hypermutants were also identified.
Conclusions:
- The mutation rate of HIV-1 did not significantly differ between HeLa and CEM-A cells.
- HIV-1 reverse transcription accuracy is comparable in both HeLa and CEM-A cell lines.
- Cell type does not appear to be a major factor influencing HIV-1 mutation rates.
Abstract:
An in vivo assay was previously developed for detecting forward mutations in human immunodeficiency virus type 1 (HIV-1) in a single cycle of replication. This system uses the lacZalpha peptide gene as a reporter for mutations, and allows for the rates and types of mutations that occur to be determined. The forward mutation rate for HIV-1 in HeLa cells was found to be 3 x 10(-5) mutations per target base pair per cycle. To test whether the mutation rate was influenced by cell type, the mutation rate of HIV-1 in CEM-A cells, a T lymphoid cell line, was determined. The mutation rate of HIV-1 reverse transcription in CEM-A cells was found to be 4 x 10(-5) mutations per target base pair per cycle. The number and types of mutations observed were similar to that in HeLa cells. Specifically, base substitution mutations predominated, and G-to-A transition mutations were the most common base substitution. G-to-A hypermutants were also characterized. The difference in HIV-1 mutation rate between HeLa and CEM-A cells was not significant, indicating that the accuracy of HIV-1 reverse transcription is comparable in both the HeLa and CEM-A cell lines.