Direct interrogation of the role of H3K9 in metazoan heterochromatin function (original) (raw)

1. Daniel J. McKay1,2,3,4,
2. Brian D. Strahl1,5,6,
3. A. Gregory Matera1,2,3,4,6 and
4. Robert J. Duronio1,2,3,4,6
5. 1Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
6. 2Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
7. 3Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
8. 4Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
9. 5Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
10. 6Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
11. Corresponding author: duronio{at}med.unc.edu

Abstract

A defining feature of heterochromatin is methylation of Lys9 of histone H3 (H3K9me), a binding site for heterochromatin protein 1 (HP1). Although H3K9 methyltransferases and HP1 are necessary for proper heterochromatin structure, the specific contribution of H3K9 to heterochromatin function and animal development is unknown. Using our recently developed platform to engineer histone genes in Drosophila, we generated H3K9R mutant flies, separating the functions of H3K9 and nonhistone substrates of H3K9 methyltransferases. Nucleosome occupancy and HP1a binding at pericentromeric heterochromatin are markedly decreased in H3K9R mutants. Despite these changes in chromosome architecture, a small percentage of H3K9R mutants complete development. Consistent with this result, expression of most protein-coding genes, including those within heterochromatin, is similar between H3K9R and controls. In contrast, H3K9R mutants exhibit increased open chromatin and transcription from piRNA clusters and transposons, resulting in transposon mobilization. Hence, transposon silencing is a major developmental function of H3K9.

• H3K9
• heterochromatin
• genomics
• Drosophila
• heterochromatin protein 1 (HP1)
• transposon

Footnotes

• Supplemental material is available for this article.

• Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.286278.116.

• Received June 27, 2016.

• Accepted August 5, 2016.

• © 2016 Penke et al.; Published by Cold Spring Harbor Laboratory Press

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