alternative products:Ccnl1 is an immediate-early gene with independently regulated isoforms,domain:Contains a RS region (arginine-serine dipeptide repeat) within the C-terminal domain which is the hallmark of the SR family of splicing factors. This region probably plays a role in protein-protein interactions.,function:Transcriptional regulator which participates in regulating the pre-mRNA splicing process. Seems to be involved in the regulation of RNA polymerase II (pol II). Functions in association with cyclin-dependent kinases (CDKs) and has a role in the second step of splicing. May be a candidate proto-oncogene in head and neck squamous cell carcinomas (HNSCC). Inhibited by the CDK-specific inhibitor p21.,miscellaneous:CCNL1 is amplified in several HNSCC. May play a critical role in the formation of loco-regional metastases and an unfavorable clinical outcome of HNSCC.,sequence caution:Probable cloning artifact.,similarity:Belongs to the cyclin family. Cyclin L subfamily.,subcellular location:More specifically found in nuclear intrachromatin granules clusters (IGC), also called nuclear speckles, which are storage compartments for nuclear proteins involved in mRNA processing.,subunit:Interacts with POLR2A via its hyperphosphorylated C-terminal domain (CTD) (By similarity). Interacts with CDC2L1 or CDC2L2, and SFRS2.,tissue specificity:Ubiquitous with higher level in thymus. Overexpression in primary tumors of head and neck squamous cell carcinomas (HNSCC).,