Bre1, an E3 Ubiquitin Ligase Required for Recruitment and Substrate Selection of Rad6 at a Promoter

Department of Biochemistry, Saint Louis University School of Medicine, 1402 South Grand Boulevard, St. Louis, MO 63104, USA.
Molecular Cell (Impact Factor: 14.02). 02/2003; 11(1):267-74. DOI: 10.1016/S1097-2765(02)00802-X
Source: PubMed


Ubiquitination of histone H2B catalyzed by Rad6 is required for methylation of histone H3 by COMPASS. We identified Bre1 as the probable E3 for Rad6's role in transcription. Bre1 contains a C3HC4 (RING) finger and is present with Rad6 in a complex. The RING finger of Bre1 is required for ubiquitination of histone H2B, methylation of lysine 4 and 79 of H3 and for telomeric silencing. Chromatin immunoprecipitation experiments indicated that both Rad6 and Bre1 are recruited to a promoter. Bre1 is essential for this recruitment of Rad6 and is dedicated to the transcriptional pathway of Rad6. These results suggest that Bre1 is the likely E3 enzyme that directs Rad6 to modify chromatin and ultimately to affect gene expression.

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    • "Euchromatin in the yeast Saccharomyces cerevisiae is characterized by Dot1-mediated H3K79 trimethylation (H3K79me3) (Briggs et al. 2002; van Leeuwen et al. 2002; Henry et al. 2003; Wood et al. 2003; Kao et al. 2004; Xiao et al. 2005; Pavri et al. 2006; Shilatifard 2006). H3K79me3, a mark closely associated with active transcription , is typically present in the coding regions of genes but absent from intergenic regions as well as subtelomeric heterochromatin (Ng et al. 2003; Pokholok et al. 2005), both of which are transcriptionally silent. "
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