The SANT domain:
A putative DNA binding domain in the SWI-SNF and ADA complexes, the transcriptional co-repressor N-CoR and TFIIIB.

by Rein Aasland(1), A. Francis Stewart(2) and Toby J. Gibson(2)

(1) Laboratory of Biotechnology, University of Bergen Bergen, Norway.
(2) Gene Expression Programme, EMBL, Meyerhofstrasse 1, D-69117 Heidelberg. Germany

Trends Biochem. Sci (TiBS) 21:87-88 (1996) - March issue.
TiBS is published by Elsevier

Abstract

We found the SANT domains as a repeated motif in N-CoR, the nuclear receptor co-repressor (Hoerlein et al., 1995). Subsequent searches revealed that SANT domains occur as doublets or singlets in many different proteins. Most notably, we find single copies of the SANT domains in the yeast nuclear proteins SWI3, ADA2 and TFIIIB''. The SWI3 protein is a componenet of the SWI/SNF complex, a global transcriptional activator (Peterson and Tamkun, 1995). The ADA2 protein is part of the ADA (or adaptor) complex (Horiuchi et al., 1995) and TFIIIB'' is a subunit of the basal trascription factor TFIIIB required for polIII transcription in yeast (Kassavetis et al., 1995).

Sequence searches with SANT domains consistently picked up the DNA binding domains of MYB-like proteins and, indeed, the SANT domains can be aligned to MYB repeats (see alignment ). A secondary structure prediction supports this observation, indicating that the SANT domains are fold into three alpha helices. The similarity of SANT domains to MYB domains strongly suggest that SANT domains are DNA binding domains.

Quinn et al. (1996) recently showed that the SWI/SNF complex has a DNA binding activity. And here is some more information on the components of the SWI/SNF complex.
A further development in the elucidation of the function of SANT-proteins comes with the identification by Brownell et al. (1996) of GCN5, another component of the ADA-complex, as a histone acetyl transferase A.

• A hyperlinked table of SANT domain proteins.
• The alignment of SANT domains and MYB repeats in colour and in GDE format
• a tree describing the relationship between the different subsets of SANT domains.
• The profiles used to search for SANT domains.
• Here is a cartoon of a selected set of SANT domain proteins.
• Here is an image of a single myb repeat bound to DNA
• Here are links to descriptions of methods and software used for the analyses.

This work was carried out at the EMBL and at the University of Bergen.
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