The BRAT1 Knockout 143B Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population, where BRAT1 gene disruption eliminates its protein function. These polyclonal cells consist of a heterogeneous pool of 143B osteosarcoma cells with mixed editing events, avoiding clonal selection and preserving biological variability. The polyclonal format simplifies experimental handling and is appropriate for functional genomic studies, signal transduction analyses, and drug sensitivity profiling. This population models BRAT1 deficiency in a human osteosarcoma context, providing a translational platform for DNA damage response research.
The 143B host cell line is a human osteosarcoma model with a homozygous TP53 R273H mutation, derived from a female patient. This TP53 defect disrupts p53 tumor suppressor activity, enhancing genomic instability and impairing apoptosis. 143B cells are widely utilized for osteosarcoma research due to their robust growth and relevance to bone cancer biology. Their p53-mutant background makes them ideal for investigating the added consequences of BRAT1 loss on DNA damage signaling and tumor cell survival.
BRAT1 functions as an ATM kinase activator in the DNA damage response, binding ATM and promoting its activation after double-strand breaks. It interacts with ATM, ATR, BRCA1, TopBP1, and p53 to scaffold checkpoint signaling. BRAT1 knockout impairs phosphorylation of downstream targets CHK2 and p53, causing defective cell cycle arrest and apoptosis. The protein also intersects with ATR-CHK1 signaling and regulates CDC25, linking it to cyclin-dependent kinase control. Overall, BRAT1 loss leads to genomic instability and compromised checkpoint maintenance.
In the 143B background, BRAT1 knockout creates a dual-deficiency model where both ATM activation and p53 function are compromised. This combination exacerbates genomic instability and may reveal synthetic lethal dependencies or druggable vulnerabilities. The model is particularly relevant for osteosarcoma, where TP53 and ATM pathway alterations frequently co-occur. It enables dissection of p53-independent checkpoint mechanisms and studies of cancer cell adaptation to DNA repair defects, offering a powerful system for therapeutic discovery.
These cells are suited for DNA damage and cancer research applications. Western blotting for phospho-CHK2 and phospho-p53, ??H2AX immunofluorescence, and Comet assays quantify DNA damage and signaling defects. Functional assessments include clonogenic survival, MTT assays for viability, flow cytometry for cell cycle, and caspase-3 cleavage assays for apoptosis. The polyclonal knockout population facilitates drug screening, chemoresistance studies, and osteosarcoma modeling. For further information regarding this product, please contact Ascent Research.
