Fig. 1. (A) Transcriptional repression by nuclear receptors is regulated by recruitment of the co-repressors N-CoR and/or SMRT. (B) The domains of N-CoR/SMRT. Repression domains (RI, RII, RIII) and SANT domains (A and B) are indicated, as are interaction domains for HDACs, nuclear receptors (I and II) and other transcription factors. (C) N-CoR—SMRT compexes. Biochemical purification techniques have revealed several different complexes recruited by N-CoR and/or SMRT (Jones et al., 2001; Li et al., 2000; Underhill et al., 2000; Wen et al., 2000; Guenther et al., 2000).