APOBEC3G Knockout HeLa Polyclonal Cells are a heterogeneous population of HeLa cells engineered by CRISPR/Cas9-mediated disruption of the APOBEC3G gene. This polyclonal knockout product is designed for studying the loss-of-function effects of APOBEC3G, a cytidine deaminase that restricts HIV-1 replication and retrotransposon mobility. The cells provide a robust model for investigating innate antiviral immunity and cancer biology without the need for single-cell cloning, preserving genetic diversity akin to the parental line.
HeLa cells are an immortalized human cervical adenocarcinoma cell line, originally derived from a patient with cervical cancer. They are widely used in biomedical research due to their robust growth characteristics, ease of genetic manipulation, and extensive characterization. As a cancer-derived line, HeLa cells exhibit dysregulated signaling, making them suitable for studying oncogenic processes and viral replication in a cancerous context. The APOBEC3G knockout in these cells allows for dissection of the gene’s role in both normal and malignant cervical epithelial biology.
APOBEC3G encodes a cytidine deaminase that catalyzes C-to-U editing in single-stranded DNA, acting as a potent restriction factor against HIV-1 and endogenous retrotransposons like LINE-1. Its expression is upregulated by type I interferons (IFN-??/??) via the JAK-STAT pathway: binding of IFNs to IFNAR1/2 activates JAK1 and TYK2, which phosphorylate STAT1 and STAT2, leading to formation of the ISGF3 complex with IRF9 and transcriptional activation through interferon-stimulated response elements (ISRE). Other upstream stimuli include IL-2 and IL-15. Mechanistically, APOBEC3G is incorporated into budding HIV-1 virions and deaminates minus-strand viral cDNA during reverse transcription, inducing lethal G-to-A hypermutation. The viral antagonist Vif counteracts this by recruiting APOBEC3G to an ElonginB-ElonginC-Cullin5 E3 ligase complex for ubiquitin-proteasomal degradation. APOBEC3G also interacts with core binding factor beta (CBF-??) and forms oligomers, which modulate its packaging and activity.
In HeLa cells, the loss of APOBEC3G eliminates a key innate antiviral mechanism, making the knockout model essential for understanding the interplay between viral restriction and cancer biology. HeLa cells are permissive to HIV-1 infection in vitro, and the absence of APOBEC3G allows for productive viral replication without Vif-mediated degradation, enabling studies of Vif function and drug resistance. Furthermore, these cells can be used to explore the contribution of APOBEC3G to cancer mutagenesis. The polyclonal nature of the knockout population reduces clonal artifacts, providing a physiologically relevant model.
Researchers can employ these cells in a wide range of assays to investigate APOBEC3G biology. Western blotting and RT-qPCR confirm gene disruption, while co-immunoprecipitation permits analysis of APOBEC3G interactions with Vif and CBF-??. HIV-1 infectivity assays and hypermutation assays (e.g., 3D-PCR or sequencing) quantify restriction activity. Interferon-stimulated STAT signaling analysis and flow cytometry can assess pathway activation. Additionally, the knockout cells are valuable for drug resistance studies targeting the Vif-APOBEC3G axis and for examining the impact of APOBEC3G deficiency on retrotransposon mobility and cancer mutations. For further information or to discuss customized applications, please contact Ascent Research.
