The CCNT2 Knockout HeLa Polyclonal Cells constitute a CRISPR/Cas9-edited polyclonal knockout cell population in which the CCNT2 gene has been disrupted. This product provides a loss-of-function model for Cyclin T2, the regulatory subunit of positive transcription elongation factor b (P-TEFb). Because the knockout population is polyclonal, it contains a heterogeneous mixture of edited alleles, offering a robust platform for studying gene function without clonal bias.
The parental HeLa cell line is an immortalized human cervical epithelial adenocarcinoma line originally derived from Henrietta Lacks in 1951. These cells are HPV18-positive and widely used in biomedical research, particularly in cancer biology, virology, and transcriptional regulation. Their stable karyotype and rapid proliferation make them suitable for a variety of loss-of-function studies.
CCNT2 heterodimerizes with CDK9 to form the P-TEFb complex, which phosphorylates Ser2 residues in the C-terminal domain (CTD) of RNA polymerase II and negative elongation factors DSIF and NELF, thereby releasing paused polymerase into productive elongation. P-TEFb activity is tightly controlled by its reversible sequestration into the inactive 7SK snRNP complex, which includes HEXIM1, LARP7, MEPCE, and 7SK snRNA. Activation involves recruitment by BRD4 and the Super Elongation Complex (SEC) containing AFF4 and ELL2, downstream of signals from NF-??B and MYC. The CCNT2 knockout disrupts this regulatory node, affecting transcription of immediate-early genes such as FOS and MYC, as well as HIV LTR-driven transcription when Tat is present.
In the HPV18-positive HeLa background, the CCNT2 knockout model is particularly relevant for investigating the interplay between viral oncoproteins and host transcriptional elongation. HPV E6 and E7 proteins inactivate p53 and Rb, respectively, and the P-TEFb pathway is linked to both cell cycle progression and p53-dependent responses. Thus, ablating CCNT2 enables dissection of how HPV-driven cancers co-opt P-TEFb to sustain aberrant gene expression and proliferation. This model also supports HIV transcription research, as HeLa cells can be engineered to express HIV Tat, which requires P-TEFb for viral transactivation.
This knockout cell pool is an ideal tool for mechanistic studies of transcriptional elongation and for drug discovery efforts targeting P-TEFb. Researchers can employ western blotting to monitor phospho-RNA Pol II CTD (Ser2) levels, RT-qPCR to quantify immediate-early gene induction, ChIP-qPCR to assess RNA Pol II promoter occupancy, and RNA-seq to profile nascent transcription. In addition, the model facilitates sensitivity screening for CDK9 inhibitors such as flavopiridol or selective clinical candidates. For additional product inquiries or technical support, please contact Ascent Research.
