Article

The H3K4 demethylase lid associates with and inhibits histone deacetylase Rpd3.

Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295. .
Molecular and Cellular Biology (Impact Factor: 5.04). 01/2009; 29(6):1401-10. DOI: 10.1128/MCB.01643-08
Source: PubMed

ABSTRACT JmjC domain-containing proteins have been shown to possess histone demethylase activity. One of these proteins is the Drosophila histone H3 lysine 4 demethylase Little imaginal discs (Lid), which has been genetically classified as a Trithorax group protein. However, contrary to the supposed function of Lid in gene activation, the biochemical activity of this protein entails the removal of a histone mark that is correlated with active transcription. To understand the molecular mechanism behind the function of Lid, we have purified a Lid-containing protein complex from Drosophila embryo nuclear extracts. In addition to Lid, the complex contains Rpd3, CG3815/Drosophila Pf1, CG13367, and Mrg15. Rpd3 is a histone deacetylase, and along with Polycomb group proteins, which antagonize the function of Trithorax group proteins, it negatively regulates transcription. By reconstituting the Lid complex, we demonstrated that the demethylase activity of Lid is not affected by its association with other proteins. However, the deacetylase activity of Rpd3 is greatly diminished upon incorporation into the Lid complex. Thus, our finding that Lid antagonizes Rpd3 function provides an explanation for the genetic classification of Lid as a positive transcription regulator.

Download full-text

Full-text

Available from: Hediye Erdjument-Bromage, Apr 29, 2014
0 Followers
 · 
127 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ataxia telangiectasia-mutated (ATM) and ataxia telangiectasia-related (ATR) kinases are conserved regulators of cellular responses to double strand breaks (DSBs). During meiosis, however, the functions of these kinases in DSB repair and the deoxyribonucleic acid (DNA) damage checkpoint are unclear. In this paper, we show that ATM and ATR have unique roles in the repair of meiotic DSBs in Drosophila melanogaster. ATR mutant analysis indicated that it is required for checkpoint activity, whereas ATM may not be. Both kinases phosphorylate H2AV (γ-H2AV), and, using this as a reporter for ATM/ATR activity, we found that the DSB repair response is surprisingly dynamic at the site of DNA damage. γ-H2AV is continuously exchanged, requiring new phosphorylation at the break site until repair is completed. However, most surprising is that the number of γ-H2AV foci is dramatically increased in the absence of ATM, but not ATR, suggesting that the number of DSBs is increased. Thus, we conclude that ATM is primarily required for the meiotic DSB repair response, which includes functions in DNA damage repair and negative feedback control over the level of programmed DSBs during meiosis.
    The Journal of Cell Biology 10/2011; 195(3):359-67. DOI:10.1083/jcb.201104121 · 9.69 Impact Factor
  • Source
    The EMBO Journal 04/2011; 30(8):1420-1. DOI:10.1038/emboj.2011.99 · 10.75 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Dynamic regulation of histone modifications is critical during development, and aberrant activity of chromatin-modifying enzymes has been associated with diseases such as cancer. Histone demethylases have been shown to play a key role in eukaryotic gene transcription; however, little is known about how their activities are coordinated in vivo to regulate specific biological processes. In Drosophila, two enzymes, dLsd1 (Drosophila ortholog of lysine-specific demethylase 1) and Lid (little imaginal discs), demethylate histone H3 at Lys 4 (H3K4), a residue whose methylation is associated with actively transcribed genes. Our studies show that compound mutation of Lid and dLsd1 results in increased H3K4 methylation levels. However, unexpectedly, Lid mutations strongly suppress dLsd1 mutant phenotypes. Investigation of the basis for this antagonism revealed that Lid opposes the functions of dLsd1 and the histone methyltransferase Su(var)3-9 in promoting heterochromatin spreading at heterochromatin-euchromatin boundaries. Moreover, our data reveal a novel role for dLsd1 in Notch signaling in Drosophila, and a complex network of interactions between dLsd1, Lid, and Notch signaling at euchromatic genes. These findings illustrate the complexity of functional interplay between histone demethylases in vivo, providing insights into the epigenetic regulation of heterochromatin/euchromatin boundaries by Lid and dLsd1 and showing their involvement in Notch pathway-specific control of gene expression in euchromatin.
    Genes & development 01/2011; 25(1):17-28. DOI:10.1101/gad.1983711 · 12.64 Impact Factor