The CDK9 Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population with functional disruption of the CDK9 gene. This heterogeneous pool provides a comprehensive loss-of-function model for studying CDK9-dependent processes without clonal selection bias. Derived from Raji B lymphocytes, these cells enable investigation of transcriptional regulation, oncogenic signaling, and viral transcription.
Raji is a human B lymphocyte cell line derived from an aggressive Burkitt’s lymphoma, a high-grade non-Hodgkin lymphoma. These cells retain mature B-cell features, including surface immunoglobulin expression, and are widely used in B-cell biology, lymphomagenesis, and immune signaling research. As a rapidly proliferating suspension line, Raji cells are amenable to high-throughput screening. Their malignant origin and reliance on transcriptional programs for survival make them particularly pertinent for modeling oncogenic kinase dependencies and apoptosis.
CDK9 is the catalytic subunit of P-TEFb, which partners with Cyclin T1 or T2 to regulate transcriptional elongation. In its inactive state, P-TEFb is bound in the 7SK snRNP complex with HEXIM1. Activation is triggered by BRD4 and upstream signals such as NF-??B. CDK9 then phosphorylates the RNA polymerase II CTD at serine 2 and negative elongation factors NELF and DSIF, relieving pausing. This drives expression of genes like c-Myc, Mcl-1, and Bcl-2, which control proliferation and apoptosis. CDK9 also serves as a host cofactor for HIV Tat-mediated transcription and is implicated in cardiac hypertrophy and inflammation.
In Raji lymphoma cells, CDK9 sustains expression of short-lived anti-apoptotic proteins such as Mcl-1, which are often elevated to block cell death. Knockout of CDK9 in this polyclonal pool leads to rapid downregulation of these survival factors and induction of apoptosis. Thus, the model captures the transcriptional addiction of lymphoma cells and mimics pharmacological CDK9 inhibition. The heterogeneous knockout population better reflects tumor genetic diversity, offering a physiologically relevant system for target validation and pharmacodynamic studies.
Applications include ChIP-qPCR for Pol II occupancy, RNA-seq for transcriptome profiling, and co-immunoprecipitation for P-TEFb complex analysis. In cancer research, viability assays (MTS/PrestoBlue) and apoptosis flow cytometry enable drug sensitivity and synthetic lethality screens. HIV transcriptional studies can utilize these cells to dissect Tat-dependent elongation. Western blotting and qRT-PCR provide rapid assessment of target engagement and downstream effectors such as Mcl-1. For further details, contact Ascent Research.
