Related Experiment Video
Updated: Feb 12, 2026
A Detailed Protocol for Characterizing the Murine C1498 Cell Line and its Associated Leukemia Mouse Model
Published on: October 14, 2016
Mouse APOBEC3 expression in NIH 3T3 cells mediates hypermutation of AKV murine leukemia virus
Stefano Boi1, Morgan E Ferrell1, Ming Zhao2
1Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA.
Abstract:
Mouse APOBEC3 (mA3) is a cytidine deaminase that can act on the single-stranded DNA reverse transcripts of retroviruses resulting in G→A hypermutation of proviral DNA. Many mA3 studies have used NIH 3T3 cells assuming that endogenous mA3 production was negligible. We developed a monoclonal antibody specific for mA3 that reveals detectable mA3 in NIH 3T3 cells and we demonstrate that AKV released from the cells undergoes G→A hypermutation. Inactivation of the mA3 gene abolished the deamination confirming that AKV hypermutation was mediated by mA3. The G→A mutations in AKV viral transcripts deviated from a normal distribution with all the mutations contained within only 20% of the transcripts. Single cell analyses revealed that the expression of mA3 in NIH 3T3 cells was limited to 20% of the cells, which likely accounted for the abnormal distribution of mutations. Endogenous NIH 3T3 mA3 was found to restrict AKV replication.
Insights
Mouse APOBEC3 (mA3) restricts retroviral replication by causing G→A hypermutation. This study found significant endogenous mA3 in NIH 3T3 cells, explaining previously observed retroviral mutations and demonstrating mA3
Area of Science:
- Virology
- Molecular Biology
- Immunology
Background:
- Mouse APOBEC3 (mA3) is a cytidine deaminase involved in innate immunity against retroviruses.
- Previous studies often assumed negligible endogenous mA3 in NIH 3T3 cells for retroviral research.
- The role of endogenous mA3 in NIH 3T3 cells and its impact on retroviral mutation patterns remained unclear.
Purpose of the Study:
- To investigate the presence and activity of endogenous mouse APOBEC3 (mA3) in NIH 3T3 cells.
- To determine if endogenous mA3 mediates G→A hypermutation in retroviral transcripts.
- To elucidate the mechanism behind the observed mutation distribution and mA3's role in restricting retroviral replication.
Main Methods:
- Development of a monoclonal antibody specific for mouse APOBEC3 (mA3).
- Detection of mA3 expression in NIH 3T3 cells using the developed antibody.
- Analysis of AKV (a retrovirus) G→A hypermutation in viral transcripts.
- Gene inactivation of mA3 to confirm its role in deamination.
- Single-cell expression analysis of mA3 in NIH 3T3 cells.
- Assessment of AKV replication in the presence of endogenous mA3.
Main Results:
- Detectable levels of endogenous mouse APOBEC3 (mA3) were found in NIH 3T3 cells.
- AKV retroviral DNA released from these cells exhibited significant G→A hypermutation.
- Inactivation of the mA3 gene abolished the observed G→A hypermutation, confirming mA3's role.
- Mutation distribution was non-uniform, with mutations concentrated in ~20% of transcripts.
- Single-cell analysis revealed mA3 expression in only ~20% of NIH 3T3 cells, explaining the mutation pattern.
- Endogenous mA3 effectively restricted AKV replication in NIH 3T3 cells.
Conclusions:
- Endogenous mouse APOBEC3 (mA3) is present and active in NIH 3T3 cells.
- mA3 mediates G→A hypermutation in AKV viral transcripts, restricting replication.
- The restricted expression of mA3 in a subset of NIH 3T3 cells explains the observed mutation distribution.
More Related Videos
Related Concept Videos
00:50What are Viruses?
01:58Cell Specific Gene Expression
01:58Cell Specific Gene Expression
01:38Receptor-mediated Endocytosis
01:40Cell-mediated Immune Responses
01:42What is Gene Expression?
Gene expression is the process in which DNA directs the synthesis of functional products, that is, proteins. Cells can regulate gene expression at various stages. It allows organisms to generate different cell types and enables cells to adapt to internal and external factors.
Genetic Information Flows from DNA to RNA to Protein
A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is made up of nucleotides and proteins consist of amino...