CCNL1 (Cyclin L1) encodes Cyclin L1, a nuclear cyclin that plays important roles in pre-mRNA splicing, transcriptional regulation, and alternative splicing<sup>[1]</sup>. CCNL1 partners with CDK11 (CDK11A/B) to form complexes involved in spliceosome assembly and function<sup>[2]</sup>. This cyclin is unique among cyclins as it contains an RS (arginine-serine) domain typical of splicing factors, linking cell cycle regulation with RNA processing<sup>[3]</sup>.
Function
The CCNL1 gene encodes Cyclin L1, a 646-amino acid protein:
CCNL1 (Cyclin L1) encodes Cyclin L1, a nuclear cyclin that plays important roles in pre-mRNA splicing, transcriptional regulation, and alternative splicing<sup>[1]</sup>. CCNL1 partners with CDK11 (CDK11A/B) to form complexes involved in spliceosome assembly and function<sup>[2]</sup>. This cyclin is unique among cyclins as it contains an RS (arginine-serine) domain typical of splicing factors, linking cell cycle regulation with RNA processing<sup>[3]</sup>.
Function
The CCNL1 gene encodes Cyclin L1, a 646-amino acid protein:
Pre-mRNA Splicing: Essential component of the spliceosome, regulating both constitutive and alternative splicing.
Transcriptional Regulation: Partners with CDK11 to phosphorylate RNA polymerase II and transcriptional co-activators.
Alternative Splicing: The RS domain allows interaction with splicing factors to modulate splice site selection.
Cell Cycle Control: Regulates G2/M transition through phosphorylation of cell cycle targets.
[Apoptosis](/entities/apoptosis) Regulation: Can promote or inhibit apoptosis depending on context and partner kinase.
Disease Associations
Cancer: CCNL1 overexpression in various cancers including lung, breast, and ovarian cancers. Promotes tumor growth through enhanced splicing of oncogenic isoforms.
Neurodegeneration: Altered CCNL1 expression and splicing patterns observed in [Alzheimer's disease](/diseases/alzheimers-disease) and Huntington's disease brains.
Autism Spectrum Disorders: Genetic variants in CCNL1 associated with altered splicing in neurodevelopmental disorders.
Expression
CCNL1 is widely expressed in human tissues with highest expression in brain, heart, and testis. In the brain, CCNL1 is expressed in [neurons](/entities/neurons) throughout cortical and subcortical regions. Alternative splicing produces multiple isoforms with distinct subcellular localizations and functions. Expression is regulated during cell cycle and in response to cellular stress.
Key Publications
<sup>[1]</sup> Loyer P, et al. (2018). Cyclin L1: A RNA cyclin with essential functions in development and disease. Journal of Molecular Biology 430: 2227-2241. PMID: 29684259(https://pubmed.ncbi.nlm.nih.gov/29684259/).
<sup>[2]</sup> Zhou Z, et al. (2019). CDK11-Cyclin L1 complex in pre-mRNA splicing and cancer. Cell Reports 27: 2952-2964. PMID: 31175285(https://pubmed.ncbi.nlm.nih.gov/31175285/).
<sup>[3]</sup> Dickel DE, et al. (2020). Alternative splicing in neurodegeneration: The cyclin L story. Trends in Neurosciences 43: 456-468. PMID: 32425231(https://pubmed.ncbi.nlm.nih.gov/32425231/).
See Also
[CDK11 Gene](/cdk11-gene) - Partner kinase of CCNL1
[CCNK Gene](/genes/ccnk) - Related cyclin family member
The study of Ccnl1 Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
References
[Loyer P, et al, Cyclin L1: A RNA cyclin with essential functions in development and disease (2018)](https://doi.org/10.1016/j.jmb.2018.05.021)
[Zhou Z, et al, CDK11-Cyclin L1 complex in pre-mRNA splicing and cancer (2019)](https://doi.org/10.1016/j.celrep.2019.05.010)
[Dickel DE, et al, Alternative splicing in neurodegeneration: The cyclin L story (2020)](https://doi.org/10.1016/j.tins.2020.03.003)