CCNT1 Knockout Jurkat Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the Jurkat T lymphocyte cell line, designed to disrupt the CCNT1 gene and impair Cyclin T1 expression. This heterogeneous knockout pool provides a loss-of-function platform for investigating Cyclin T1-dependent transcriptional elongation and P-TEFb complex activity without clonal artifacts.
Jurkat cells are an immortalized line from human acute T cell leukemia, widely used as a suspension model for T cell receptor signaling, apoptosis, and HIV-1 infection. Their lymphoid context makes them ideal for studying the transcriptional elongation mechanisms underlying T cell activation and viral transactivation. In this CCNT1 knockout background, the requirement for Cyclin T1 in these processes can be directly assessed.
CCNT1 encodes Cyclin T1, the regulatory subunit of P-TEFb, which partners with CDK9 to phosphorylate Ser2 of the RNA polymerase II CTD, releasing paused polymerase into productive elongation. Cyclin T1 is essential for HIV-1 Tat transactivation: Tat binds TAR RNA and recruits P-TEFb to overcome elongation arrest at the viral LTR. Its activity is controlled by sequestration in the HEXIM1/7SK snRNP complex and competitive release by BRD4, and it serves as a scaffold for super elongation complex assembly via AFF1 and AFF4. Upstream signals from the TCR, NF-??B, and PMA/ionomycin stimulation trigger P-TEFb activation, while key downstream targets include immediate early genes such as c-MYC and FOS.
CCNT1 disruption in Jurkat cells impairs P-TEFb-dependent elongation, creating a model to study HIV latency reversal, T cell activation gene programs, and the role of Cyclin T1 in leukemia proliferation. The knockout background allows dissection of SEC-dependent and -independent gene regulation and validation of CDK9 inhibitor specificity. Researchers can also explore compensatory induction of alternative P-TEFb regulatory pathways in a lymphoid environment.
This polyclonal knockout cell product supports diverse assays: western blot for Cyclin T1 and phospho-RNA Pol II Ser2, ChIP-qPCR for Pol II occupancy, co-immunoprecipitation of CDK9/Cyclin T1, HIV LTR reporter assays, and RNA-seq to quantify elongation efficiency. Flow cytometry for CD69/CD25 monitors T cell activation, while drug sensitivity testing with flavopiridol enables inhibitor profiling. For technical inquiries, custom orders, or experimental support, please contact Ascent Research.
