InterPro domain: IPR031120

This entry includes HIR1/HIR2 from yeasts and HIRA from animals. They are WD-repeat containing proteins required for regulation of histone gene transcription.

The budding yeast HIR complex is composed of Hir1, Hir2, Hir3 and Hpc2, and interacts with ASF1 [ 1 , 2 ]. The HIR complex cooperates with ASF1 to promote replication-independent chromatin assembly. The HIR complex is also required for the periodic repression of three of the four histone gene loci during cell cycle as well as for autogenous regulation of the HTA1-HTB1 locus by H2A and H2B. DNA-binding by the HIR complex may repress transcription by inhibiting nucleosome remodeling by the SWI/SNF complex. The HIR complex may also be required for transcriptional silencing of centromeric, telomeric and mating-type loci in the absence of CAF-1 [ 3 ].

1. Yeast ASF1 protein is required for cell cycle regulation of histone gene transcription. Genetics 158, 587-96
2. Characterization of HIR1 and HIR2, two genes required for regulation of histone gene transcription in Saccharomyces cerevisiae. Mol. Cell. Biol. 13, 28-38
3. The HIR corepressor complex binds to nucleosomes generating a distinct protein/DNA complex resistant to remodeling by SWI/SNF. Genes Dev. 19, 2534-9