The BRD3 Knockout HT29 Polyclonal Cells product comprises a polyclonal population of HT29 colorectal adenocarcinoma cells engineered via CRISPR/Cas9-mediated disruption of the BRD3 gene. This knockout model enables loss-of-function studies of the bromodomain-containing protein 3 (BRD3) in a human colorectal cancer background. The polyclonal format provides a diverse, heterogeneous cell pool, reflecting the stochastic nature of CRISPR-induced edits without clonal selection.
The host HT29 cell line was derived from a primary colorectal adenocarcinoma of a 44-year-old female and is widely utilized as a model for intestinal epithelial biology and colon cancer. HT29 cells exhibit an undifferentiated phenotype, are tumorigenic, and retain the capacity to secrete mucins under certain conditions, making them suitable for investigating epithelial?Cmesenchymal transitions and colorectal tumor progression. This established line provides a physiologically relevant context for probing BRD3 function in intestinal epithelial malignancies.
BRD3 is a member of the BET bromodomain protein family, which recognizes acetylated lysine residues on histone H4. It recruits positive transcription elongation factor b (P-TEFb, CDK9/Cyclin T1) and the Mediator complex to chromatin, facilitating RNA polymerase II elongation at target genes. BRD3 is a key co-activator of MYC and regulates downstream targets such as BCL-2, CDK6, and FOSL1, linking acetylated histone states to cell cycle progression and survival. Upstream, its activity is regulated by histone acetyltransferases CBP/p300 and acetylated H4, and it participates in a MYC positive feedback loop. BRD3 also interacts with BET members BRD2 and BRD4. In this knockout model, BRD3 disruption abrogates P-TEFb recruitment to oncogenic loci, attenuating MYC-driven transcription and growth-promoting signaling.
In the HT29 colorectal adenocarcinoma background, BRD3 knockout disrupts the acetyl-histone?CBET protein axis that sustains oncogenic transcription. This loss-of-function model allows researchers to dissect BRD3-specific contributions independently of other BET proteins, which is particularly valuable given the broad expression of BRD2 and BRD4. The engineered cells exhibit impaired MYC regulatory network activity and reduced expression of anti-apoptotic genes like BCL-2, leading to decreased proliferation and enhanced apoptosis. Consequently, this model serves as a platform for validating BRD3??s role in colon cancer cell maintenance and for evaluating the cellular response to BET bromodomain inhibitors such as JQ1.
Typical applications include interrogating BRD3-dependent transcriptional programs via RNA-seq and ChIP-qPCR of MYC and FOSL1 promoters. The cells support proliferation (MTT/BrdU), apoptosis (Annexin V), and colony formation assays to assess BRD3 dependency. Researchers also use this knockout model to validate BET inhibitor specificity, monitoring target expression by RT-qPCR and immunoblotting. The polyclonal format minimizes clonal artifacts, making it robust for drug screening and functional genomics. For further details, please contact Ascent Research.
