The APOBEC3C Knockout HCT 116 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population engineered to disrupt the human APOBEC3C gene, providing a loss-of-function model for studying cytidine deaminase functions. This polyclonal pool contains a heterogeneous mixture of edited alleles, enabling robust population-level analyses without single-cell cloning artifacts. The knockout model is suitable for investigating APOBEC3C-dependent processes in innate immunity, DNA editing, and cancer mutagenesis.
The parental HCT 116 cell line is a widely used model of colorectal carcinoma, derived from a human colon adenocarcinoma. These epithelial cells exhibit microsatellite instability due to MLH1 deficiency, harbor an oncogenic KRAS G13D mutation, and maintain a near-diploid karyotype. The mismatch repair?Cdeficient background makes HCT 116 particularly permissive to accumulation of spontaneous mutations and is commonly employed to study tumorigenesis, drug responses, and DNA repair mechanisms.
APOBEC3C, a single-stranded DNA cytidine deaminase, catalyzes C-to-U conversion, contributing to antiviral defense and cancer mutagenesis. Its expression is upregulated by interferon signaling through STAT1/STAT2 and NF-??B. Deamination by APOBEC3C generates abasic sites and uracil lesions that, if unrepaired, lead to C-to-T transition mutations. The protein interacts with PCNA and replication protein A (RPA), linking its activity to DNA replication and repair. Downstream, APOBEC3C-mediated DNA damage can activate p53 and trigger DNA damage response pathways. HIV-1 Vif protein counteracts APOBEC3C by promoting its degradation. Additionally, APOBEC3C cooperates with other deaminases such as AID and APOBEC3 family members, and its activity is processed by base excision repair (BER) components including UNG2 and TET enzymes.
In the HCT 116 background, APOBEC3C knockout provides a clean system to dissect its contribution to spontaneous mutagenesis in mismatch repair?Cdeficient tumors. Since HCT 116 cells lack MLH1-dependent repair, APOBEC3C-induced uracils are more likely to persist and yield C-to-T mutations, mimicking the mutation signatures observed in many colorectal, breast, and lung cancers. This model thus allows researchers to assess how APOBEC3C activity shapes the mutational landscape in colon cancer and to explore the interplay between APOBEC enzymes and DNA repair pathways.
This polyclonal knockout product is suitable for a range of applications, including quantification of mutation signatures through sequencing, measurement of cellular proliferation and drug sensitivity changes upon APOBEC3C loss, and viral infectivity assays to study innate restriction mechanisms. Western blotting can confirm APOBEC3C protein depletion, while RNA-seq enables transcriptome-wide assessment of compensatory changes. The cells can also serve as a background for reintroducing APOBEC3C variants to probe structure-function relationships. For additional details or custom requests, please contact Ascent Research.
