The APOBEC3A Knockout HCT 116 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the HCT 116 human colorectal adenocarcinoma line. This product provides loss-of-function of the APOBEC3A gene, eliminating expression of the cytosine deaminase. As a polyclonal pool rather than a clonal isolate, it offers a heterogeneous knockout background suitable for population-level functional studies without single-cell artifacts. Targeting disruption of APOBEC3A via CRISPR/Cas9 results in complete absence of APOBEC3A protein, making these cells a powerful model for studying DNA editing and innate immune functions.
HCT 116 is a widely utilized human colorectal carcinoma cell line derived from a male patient, serving as an intestinal epithelial cell model. These cells maintain epithelial morphology and exhibit rapid growth, and they are extensively characterized in cancer biology research. Notably, HCT 116 cells carry mutations in DNA mismatch repair genes and TP53, rendering them susceptible to genomic instability, which is relevant when investigating APOBEC3A-induced mutagenesis.
APOBEC3A functions as a single-stranded DNA cytosine deaminase, catalyzing C-to-U conversions that result in C-to-T hypermutations and restriction of retroviruses and retrotransposons. Its expression is induced by interferons (IFN-??/??) via the JAK/STAT pathway: IFNAR engagement activates TYK2 and JAK1, which phosphorylate STAT1/2, leading to formation of the ISGF3 complex with IRF9 and transcriptional activation of APOBEC3A. Additionally, NF-??B signaling and direct interaction with ssDNA and APOBEC3B modulate its activity. Downstream, APOBEC3A targets viral genomes and cellular DNA, generating mutation signatures linked to both antiviral defense and oncogenesis.
In the HCT 116 background, APOBEC3A-mediated DNA editing contributes to genomic mutation load, potentially promoting tumor evolution and therapy resistance. Knockout of APOBEC3A eliminates this mutagenic pressure, allowing dissection of its role in spontaneous and damage-induced C-to-T transitions. Moreover, removal of APOBEC3A may blunt interferon-triggered innate immune responses, providing a platform to study tumor cell-intrinsic immune pathways. This model holds particular value for colorectal cancer research, where APOBEC mutation signatures have been correlated with disease progression.
Applications include deaminase activity assays, western blotting, and immunofluorescence to confirm knockout and probe protein interactions. Viral infectivity assays using HIV, HBV, or HPV can quantify loss of restriction, while RT-qPCR reveals changes in interferon-stimulated gene expression. Next-generation sequencing enables genome-wide mutation signature analysis to map APOBEC3A-dependent off-target editing. This knockout reagent thus supports investigations in viral restriction, cancer mutagenesis, DNA repair, and innate immune signaling. For further technical inquiries, contact Ascent Research.
