Molecular Cell
Volume 9, Issue 6, June 2002, Pages 1297-1305
Journal home page for Molecular Cell

Article
Cti6, a PHD Domain Protein, Bridges the Cyc8-Tup1 Corepressor and the SAGA Coactivator to Overcome Repression at GAL1

https://doi.org/10.1016/S1097-2765(02)00545-2Get rights and content
Under an Elsevier user license
open archive

Abstract

The yeast Cyc8 and Tup1 proteins form a corepressor complex that, when tethered to DNA, turns off transcription. Release of the Cyc8-Tup1 corepressor from a promoter has been considered as a prerequisite for subsequent transcriptional activation. Contrasting this, we demonstrate that Cyc8-Tup1 is continuously associated with target promoters under both repressive and inducing conditions. At the GAL1 promoter, Cyc8-Tup1 facilitates recruitment of SAGA (Spt-Ada-Gcn5-acetyltranferase) via Cti6, a PHD domain protein that physically links the Cyc8-Tup1 and SAGA complexes. Lack of functional corepressor renders GAL1 transcription largely independent of specific SAGA subunits. Thus, corepressor's release is not the mechanism of derepression; instead, it is the coactivator complex that alleviates Cyc8-Tup1-mediated repression under induction conditions.

Cited by (0)

3

Present address: Imperial Cancer Research Fund Clare Hall Laboratories, Blanche Lane, South Mimms EN6 3LD, United Kingdom.

4

Present address: National Institute for Medical Research, Mill Hill, London, United Kingdom.