SMART: Cir_N domain annotation

Cir_N N-terminal domain of CBF1 interacting co-repressor CIR

SMART accession number:	SM01083
Description:	This is a 45 residue conserved region at the N-terminal end of a family of proteins referred to as CIRs (CBF1-interacting co-repressors). 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 (PUBMED:9874765).
Interpro abstract (IPR019339):	This entry represents a 45 residue conserved domain that is found at the N-terminal end of a family of proteins referred to as CIRs (CBF1-interacting co-repressors). 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 [(PUBMED:9874765)]. It may also modulate splice site selection during alternative splicing of pre-mRNAs.
Family alignment:	View or

There are 297 Cir_N domains in 297 proteins in SMART's nrdb database.

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Evolution (species in which this domain is found)
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This tree shows only several representative species. The complete taxonomic breakdown of all proteins with Cir_N domain is also avaliable.

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Go to specific node: Anopheles gambiae, Arabidopsis thaliana, Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens, Mus musculus, Rattus norvegicus, Saccharomyces cerevisiae, Takifugu rubripes
Cellular role (predicted cellular role)
Cellular role: transcription
Literature (relevant references for this domain)
Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.
- Hsieh JJ, Zhou S, Chen L, Young DB, Hayward SD
- CIR, a corepressor linking the DNA binding factor CBF1 to the histonedeacetylase complex.
- Proc Natl Acad Sci U S A. 1999; 96: 23-8
- Display abstract
- CBF1 is a member of the CSL family of DNA binding factors, which mediateeither transcriptional repression or transcriptional activation. CSLproteins play a central role in Notch signaling and in Epstein-Barrvirus-induced immortalization. Notch is a transmembrane protein involvedin cell-fate decisions, and the cytoplasmic domain of Notch (NotchIC)targets CBF1. The Epstein-Barr virus-immortalizing protein EBNA2 activatesboth cellular and viral gene expression by targeting CBF1 and mimickingNotchIC. We have examined the mechanism of CBF1-mediated repression andshow that CBF1 binds to a unique corepressor, CBF1 interacting corepressor(CIR). A CIR homolog is encoded by Caenorhabditis elegans, indicating thatCIR is evolutionarily conserved. Two CBF1 mutants that were unable to bindCIR did not function as repressors, suggesting that targeting of CIR toCBF1 is an important component of repression. When expressed as a Gal4fusion protein, CIR repressed reporter gene expression. CIR binds tohistone deacetylase and to SAP30 and serves as a linker between CBF1 andthe histone deacetylase complex.
Links (links to other resources describing this domain)
PFAM Cir_N
INTERPRO IPR019339

PFAM	Cir_N
INTERPRO	IPR019339