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

University of Toronto, Toronto, Ontario, Canada
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.

Download full-text


Available from: Jim Dover
  • Source
    • "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. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Here we show that the Ino80 chromatin remodeling complex (Ino80C) directly prevents euchromatin from invading transcriptionally silent chromatin within intergenic regions and at the border of euchromatin and heterochromatin. Deletion of Ino80C subunits leads to increased H3K79 methylation and noncoding RNA polymerase II (Pol II) transcription centered at the Ino80C-binding sites. The effect of Ino80C is direct, as it blocks H3K79 methylation by Dot1 in vitro. Heterochromatin stimulates the binding of Ino80C in vitro and in vivo. Our data reveal that Ino80C serves as a general silencing complex that restricts transcription to gene units in euchromatin. © 2015 Xue et al.; Published by Cold Spring Harbor Laboratory Press.
    Full-text · Article · Feb 2015 · Genes & Development
  • Source
    • "It contains a conserved RING finger domain in its carboxy terminus (Crowe and Candido, 2004) and interacts with the E2 conjugating enzyme UBC-1 (Crowe and Candido, 2004). RFP-1 homologues in other systems, including BRE1 from yeast and rat Staring, have been shown to have E3 ligase activity (Chin et al., 2002; Ishino et al., 2014; Liu et al., 2009; Wood et al., 2003; Xuan et al., 2013). Fig. 3. Loss of rfp-1 enhances overproliferation of glp-1(ar202gf ). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The level of stem cell proliferation must be tightly controlled for proper development and tissue homeostasis. Multiple levels of gene regulation are often employed to regulate stem cell proliferation to ensure that the amount of proliferation is aligned with the needs of the tissue. Here we focus on proteasome-mediated protein degradation as a means of regulating the activities of proteins involved in controlling the stem cell proliferative fate in the C. elegans germ line. We identify five potential E3 ubiquitin ligases, including the RFP-1 RING finger protein, as being involved in regulating proliferative fate. RFP-1 binds to MRG-1, a homologue of the mammalian chromodomain-containing protein MRG15 (MORF4L1), which has been implicated in promoting the proliferation of neural precursor cells. We find that C. elegans with reduced proteasome activity, or that lack RFP-1 expression, have increased levels of MRG-1 and a shift towards increased proliferation in sensitized genetic backgrounds. Likewise, reduction of MRG-1 partially suppresses stem cell overproliferation. MRG-1 levels are controlled independently of the spatially regulated GLP-1/Notch signalling pathway, which is the primary signal controlling the extent of stem cell proliferation in the C. elegans germ line. We propose a model in which MRG-1 levels are controlled, at least in part, by the proteasome, and that the levels of MRG-1 set a threshold upon which other spatially regulated factors act in order to control the balance between the proliferative fate and differentiation in the C. elegans germ line. © 2015. Published by The Company of Biologists Ltd.
    Full-text · Article · Jan 2015 · Development
  • Source
    • "In yeast, H2BK123ub1 is catalyzed by the concerted efforts of the ubiquitin-conjugating enzyme (E2) Rad6 and the RING finger domain-containing ubiquitin ligase (E3) Bre1 (Robzyk et al. 2000; Hwang et al. 2003; Wood et al. 2003a). Similar to other E3 ligases, Bre1 serves as the substrate recognition module for the complex and is important for the recruitment of Rad6 to chromatin (Wood et al. 2003a). Studies have also found that the polymeraseassociated factor (PAF) complex associates with Rad6 and facilitates its recruitment to gene bodies (Ng et al. 2003; Wood et al. 2003b; Xiao et al. 2005). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Monoubiquitylation of histone H2B on Lys123 (H2BK123ub1) plays a multifaceted role in diverse DNA-templated processes, yet the mechanistic details by which this modification is regulated are not fully elucidated. Here we show in yeast that H2BK123ub1 is regulated in part through the protein stability of the E3 ubiquitin ligase Bre1. We found that Bre1 stability is controlled by the Rtf1 subunit of the polymerase-associated factor (PAF) complex and through the ability of Bre1 to catalyze H2BK123ub1. Using a domain in Rtf1 that stabilizes Bre1, we show that inappropriate Bre1 levels lead to defects in gene regulation. Collectively, these data uncover a novel quality control mechanism used by the cell to maintain proper Bre1 and H2BK123ub1 levels, thereby ensuring proper control of gene expression.
    Preview · Article · Aug 2014 · Genes & Development
Show more