Developmental control of gene copy number by repression of replication initiation and fork progression.

Published

Journal Article

Precise DNA replication is crucial for genome maintenance, yet this process has been inherently difficult to study on a genome-wide level in untransformed differentiated metazoan cells. To determine how metazoan DNA replication can be repressed, we examined regions selectively under-replicated in Drosophila polytene salivary glands, and found they are transcriptionally silent and enriched for the repressive H3K27me3 mark. In the first genome-wide analysis of binding of the origin recognition complex (ORC) in a differentiated metazoan tissue, we find that ORC binding is dramatically reduced within these large domains, suggesting reduced initiation as one mechanism leading to under-replication. Inhibition of replication fork progression by the chromatin protein SUUR is an additional repression mechanism to reduce copy number. Although repressive histone marks are removed when SUUR is mutated and copy number restored, neither transcription nor ORC binding is reinstated. Tethering of the SUUR protein to a specific site is insufficient to block replication, however. These results establish that developmental control of DNA replication, at both the initiation and elongation stages, is a mechanism to change gene copy number during differentiation.

Full Text

Duke Authors

Cited Authors

  • Sher, N; Bell, GW; Li, S; Nordman, J; Eng, T; Eaton, ML; Macalpine, DM; Orr-Weaver, TL

Published Date

  • January 2012

Published In

Volume / Issue

  • 22 / 1

Start / End Page

  • 64 - 75

PubMed ID

  • 22090375

Pubmed Central ID

  • 22090375

Electronic International Standard Serial Number (EISSN)

  • 1549-5469

Digital Object Identifier (DOI)

  • 10.1101/gr.126003.111

Language

  • eng

Conference Location

  • United States