The CCNL1 knockout HEK293T polyclonal cells are a CRISPR/Cas9-edited mammalian cell population designed to disrupt the CCNL1 gene encoding cyclin L1. This polyclonal product consists of a heterogeneous pool of cells carrying various CRISPR-mediated gene disruptions, providing a physiologically relevant loss-of-function model without the clonal selection that could introduce cell line-specific artifacts. The knockout format enables robust investigation of CCNL1-dependent processes in a widely used human cell background, offering a versatile tool for functional genomics, splicing research, and disease modeling.
The host cell line, HEK293T, is a human embryonic kidney epithelial derivative immortalized with sheared adenovirus 5 DNA and stably expressing the SV40 large T antigen. This modification permits high-efficiency episomal replication of plasmids carrying the SV40 origin, making HEK293T cells a cornerstone for transient transfection, protein expression, lentiviral packaging, and CRISPR-based genome editing. Their epithelial origin and robust growth characteristics further support scalable experimental designs, including high-throughput screening and multi-omics analyses.
Cyclin L1 is a regulatory subunit of cyclin-dependent kinases CDK11, CDK12, and CDK13, which play critical roles in transcription and splicing. CCNL1 interacts directly with these kinases and the RNA polymerase II C-terminal domain (CTD), promoting phosphorylation at Ser2 and Ser5 residues required for productive transcriptional elongation and co-transcriptional pre-mRNA splicing. The CCNL1-CDK complexes also phosphorylate SR splicing factors, such as SF2/ASF, modulating spliceosome assembly. Upstream, mitogenic signals through MAPK and PI3K-Akt pathways activate cyclin L1 expression and activity, linking cell growth to gene expression programs. Consequently, CCNL1 acts as a nexus integrating cell signaling with RNA processing machinery, and its disruption leads to aberrant splicing patterns and altered gene expression.
In the HEK293T context, CCNL1 knockout perturbs the tightly coupled processes of RNA polymerase II transcription and co-transcriptional splicing. HEK293T cells exhibit high metabolic activity and robust gene expression, making them an ideal system to study the acute effects of splicing factor loss. Knockout of CCNL1 in these cells can reveal changes in transcript isoform diversity, splicing efficiency, and expression of genes involved in proliferation and apoptosis. This model thus provides a platform to dissect how cyclin L1-dependent phosphorylation events impact global splicing fidelity and the cellular response to growth and stress cues.
Researchers can employ these polyclonal knockout cells for a variety of applications, including transcriptome-wide splicing analysis via RNA-seq, targeted RT-qPCR quantification of splicing isoforms, and protein-level validation using phospho-specific antibodies against the RNA Pol II CTD or SR proteins. Co-immunoprecipitation experiments can assess CCNL1-CDK interactions, while immunofluorescence microscopy enables tracking changes in nuclear speckle organization. Functional assays such as proliferation and apoptosis measurements help link splicing defects to cellular phenotypes. These cells are also suitable for drug screening campaigns aimed at identifying small-molecule modulators of spliceosome activity. For further details, please contact Ascent Research.
