The BRCC3 Knockout A-549 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal knockout cell population in the A-549 human lung adenocarcinoma background, designed to ablate BRCC3 expression. This loss-of-function model enables detailed investigation of BRCC3, a deubiquitinase that plays a central role in DNA interstrand crosslink repair and mitotic checkpoint regulation. The polyclonal nature of the knockout population preserves genetic heterogeneity while ensuring robust disruption of the target gene.
A-549 cells were originally derived from a 58-year-old male patient with lung adenocarcinoma and display features characteristic of type II alveolar epithelial cells. They are a widely accepted model for non-small cell lung cancer research, retaining critical signaling pathways and an adherent epithelial morphology. Their use in drug resistance studies and DNA damage response assays is well established, making them an optimal host for studying BRCC3 function in a clinically relevant context.
BRCC3 is a deubiquitinase that functions as the catalytic subunit of the BRCA1-A and BRISC complexes. Following activation by upstream kinases ATM and ATR, BRCC3 interacts with BRCA1, BARD1, ABRAXAS1, RAP80, and MERIT40 to assemble the BRCA1-A complex at DNA damage sites. This complex specifically deubiquitinates FANCD2 and FANCI, downstream targets of the Fanconi anemia core E3 ligase complex, which is essential for the coordination of interstrand crosslink repair. BRCC3-mediated deubiquitination promotes RAD51 foci formation and enforces G2/M and S-phase cell cycle checkpoints. Loss of BRCC3 disrupts these events, leading to impaired homologous recombination repair, defective checkpoint control, and increased genomic instability.
In the A-549 lung adenocarcinoma model, disruption of BRCC3 provides a powerful tool to explore tumor-specific DNA repair dependencies and therapy resistance mechanisms. A-549 cells are frequently used to test responses to DNA crosslinking agents such as mitomycin C and cisplatin, and BRCC3 deficiency in this background allows assessment of altered drug sensitivity, repair pathway utilization, and chromosomal instability. This model is particularly valuable for studying BRCA-proficient cancers and Fanconi anemia pathway defects, as BRCC3 activity is critical for FANCD2/FANCI deubiquitination and downstream repair. Consequently, it supports research into synthetic lethality strategies and identification of novel therapeutic targets in lung adenocarcinoma.
Key applications include monitoring FANCD2 ubiquitination status by western blotting, visualizing RAD51 and ??H2AX foci via immunofluorescence, and performing cell viability assays with crosslinking agents. The model can also be applied to co-immunoprecipitation analyses of BRCA1-A complex assembly, flow cytometry for cell cycle profiling, comet assays to measure DNA fragmentation, RNA-seq transcriptomic studies, and clonogenic survival assays to evaluate long-term growth effects. Additionally, it is suitable for high-throughput screening of small-molecule inhibitors targeting deubiquitinase activity or the Fanconi anemia pathway. For further information, please contact Ascent Research.
