This domain family is found in eukaryotes, and is approximately 100 amino acids in length. The family is found in association with . There is a single completely conserved residue Y that may be functionally important. Cwc25 has been identified to associate with pre-mRNA splicing factor Cef1/Ntc85, a component of the Prp19-associated complex (NTC) involved in spliceosome activation. Cwc25 is neither tightly associated with NTC nor required for spliceosome activation, but is required for the first catalytic reaction.
This entry represents a 45 residue conserved domain found at the N-terminal end CIR protein (CBF1-interacting co-repressor, also known as corepressor interacting with RBPJ 1). This domain can be found in the fungal CWC25 family members and mammlian LENG1 (leukocyte receptor cluster member 1) protein.CBF1 (centromere-binding factor 1) acts as a transcription factor that causes repression by binding specifically to GTGGGAA motifs in responsive promoters, and it requires CIR as a co-repressor. CIR binds to histone deacetylase and to SAP30 and serves as a linker between CBF1 and the histone deacetylase complex []. CIR also plays a role in alternative splicing []. Budding yeast Cwc25 is a pre-mRNA-splicing factor involved in pre-mRNA splicing [].
