Involved in pre-mRNA splicing. May induce cell death, possibly by acting on the transcription and RNA processing of apoptosis-related factors. Interacts with CDK11A, CDK11B, CDK12, CDK13 and POLR2A, the hyperphosphorylated C-terminal domain (CTD) of RNA polymerase II. May form a ternary complex with CDK11B and casein kinase II (CKII). Interacts with pre-mRNA-splicing factors, including at least SRSF1, SRSF2 AND SRSF7/SLU7. 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 (By similarity). Belongs to the cyclin family. Cyclin L subfamily.