SUMMARY PARAGRAPH for HIR1
Hir1p is a nonessential corepressor of histone gene transcription; like other corepressors, it appears not to directly contact DNA, but can repress transcription when artificially recruited to yeast promoters (4, 2, 8). Hir1p and corepressor Hir2p help control the cell cycle regulation of transcription of histone genes HTA1, HTB1, HHT1, HHT2, HHF1, and HHF2 (1). Hir1p and Hir2p coimmunoprecipitate from yeast cell extracts, and may act as a complex (4). Hir1p has a nuclear targeting signal and two separate repression domains; the domain in the N-terminus of the protein contains copies of the WD40 motif, as found in corepressor Tup1p (1). These WD40 repeats are often implicated in protein-protein interactions; in Hir1p they functionally interact with transcriptional regulators Spt4p, Spt5p, and Spt6p (2). The human disease called DiGeorge Syndrome is likely caused by the loss of one copy of the HIRA gene, which contains features present in yeast HIR1 and HIR2 (9).
Last updated: 1999-09-01