Allele-specific transcriptional elongation regulates monoallelic expression of the <it>IGF2BP1 </it>gene

<p>Abstract</p> <p>Background</p> <p>Random monoallelic expression contributes to phenotypic variation of cells and organisms. However, the epigenetic mechanisms by which individual alleles are randomly selected for expression are not known. Taking cues from chromatin s...

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Main Authors: Thomas Brandon J, Rubio Eric D, Krumm Niklas, Broin Pilib Ó, Bomsztyk Karol, Welcsh Piri, Greally John M, Golden Aaron A, Krumm Anton
Format: Article
Language:English
Published: BMC 2011-08-01
Series:Epigenetics & Chromatin
Online Access:http://www.epigeneticsandchromatin.com/content/4/1/14
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author Thomas Brandon J
Rubio Eric D
Krumm Niklas
Broin Pilib Ó
Bomsztyk Karol
Welcsh Piri
Greally John M
Golden Aaron A
Krumm Anton
author_facet Thomas Brandon J
Rubio Eric D
Krumm Niklas
Broin Pilib Ó
Bomsztyk Karol
Welcsh Piri
Greally John M
Golden Aaron A
Krumm Anton
author_sort Thomas Brandon J
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Random monoallelic expression contributes to phenotypic variation of cells and organisms. However, the epigenetic mechanisms by which individual alleles are randomly selected for expression are not known. Taking cues from chromatin signatures at imprinted gene loci such as the insulin-like growth factor 2 gene 2 (<it>IGF2</it>), we evaluated the contribution of CTCF, a zinc finger protein required for parent-of-origin-specific expression of the <it>IGF2 </it>gene, as well as a role for allele-specific association with DNA methylation, histone modification and RNA polymerase II.</p> <p>Results</p> <p>Using array-based chromatin immunoprecipitation, we identified 293 genomic loci that are associated with both CTCF and histone H3 trimethylated at lysine 9 (H3K9me3). A comparison of their genomic positions with those of previously published monoallelically expressed genes revealed no significant overlap between allele-specifically expressed genes and colocalized CTCF/H3K9me3. To analyze the contributions of CTCF and H3K9me3 to gene regulation in more detail, we focused on the monoallelically expressed <it>IGF2BP1 </it>gene. <it>In vitro </it>binding assays using the CTCF target motif at the <it>IGF2BP1 </it>gene, as well as allele-specific analysis of cytosine methylation and CTCF binding, revealed that CTCF does not regulate mono- or biallelic <it>IGF2BP1 </it>expression. Surprisingly, we found that RNA polymerase II is detected on both the maternal and paternal alleles in B lymphoblasts that express <it>IGF2BP1 </it>primarily from one allele. Thus, allele-specific control of RNA polymerase II elongation regulates the allelic bias of <it>IGF2BP1 </it>gene expression.</p> <p>Conclusions</p> <p>Colocalization of CTCF and H3K9me3 does not represent a reliable chromatin signature indicative of monoallelic expression. Moreover, association of individual alleles with both active (H3K4me3) and silent (H3K27me3) chromatin modifications (allelic bivalent chromatin) or with RNA polymerase II also fails to identify monoallelically expressed gene loci. The selection of individual alleles for expression occurs in part during transcription elongation.</p>
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spelling doaj.art-b73d9d4b4fae4b3588c19ff5280edc8c2022-12-22T03:26:33ZengBMCEpigenetics & Chromatin1756-89352011-08-01411410.1186/1756-8935-4-14Allele-specific transcriptional elongation regulates monoallelic expression of the <it>IGF2BP1 </it>geneThomas Brandon JRubio Eric DKrumm NiklasBroin Pilib ÓBomsztyk KarolWelcsh PiriGreally John MGolden Aaron AKrumm Anton<p>Abstract</p> <p>Background</p> <p>Random monoallelic expression contributes to phenotypic variation of cells and organisms. However, the epigenetic mechanisms by which individual alleles are randomly selected for expression are not known. Taking cues from chromatin signatures at imprinted gene loci such as the insulin-like growth factor 2 gene 2 (<it>IGF2</it>), we evaluated the contribution of CTCF, a zinc finger protein required for parent-of-origin-specific expression of the <it>IGF2 </it>gene, as well as a role for allele-specific association with DNA methylation, histone modification and RNA polymerase II.</p> <p>Results</p> <p>Using array-based chromatin immunoprecipitation, we identified 293 genomic loci that are associated with both CTCF and histone H3 trimethylated at lysine 9 (H3K9me3). A comparison of their genomic positions with those of previously published monoallelically expressed genes revealed no significant overlap between allele-specifically expressed genes and colocalized CTCF/H3K9me3. To analyze the contributions of CTCF and H3K9me3 to gene regulation in more detail, we focused on the monoallelically expressed <it>IGF2BP1 </it>gene. <it>In vitro </it>binding assays using the CTCF target motif at the <it>IGF2BP1 </it>gene, as well as allele-specific analysis of cytosine methylation and CTCF binding, revealed that CTCF does not regulate mono- or biallelic <it>IGF2BP1 </it>expression. Surprisingly, we found that RNA polymerase II is detected on both the maternal and paternal alleles in B lymphoblasts that express <it>IGF2BP1 </it>primarily from one allele. Thus, allele-specific control of RNA polymerase II elongation regulates the allelic bias of <it>IGF2BP1 </it>gene expression.</p> <p>Conclusions</p> <p>Colocalization of CTCF and H3K9me3 does not represent a reliable chromatin signature indicative of monoallelic expression. Moreover, association of individual alleles with both active (H3K4me3) and silent (H3K27me3) chromatin modifications (allelic bivalent chromatin) or with RNA polymerase II also fails to identify monoallelically expressed gene loci. The selection of individual alleles for expression occurs in part during transcription elongation.</p>http://www.epigeneticsandchromatin.com/content/4/1/14
spellingShingle Thomas Brandon J
Rubio Eric D
Krumm Niklas
Broin Pilib Ó
Bomsztyk Karol
Welcsh Piri
Greally John M
Golden Aaron A
Krumm Anton
Allele-specific transcriptional elongation regulates monoallelic expression of the <it>IGF2BP1 </it>gene
Epigenetics & Chromatin
title Allele-specific transcriptional elongation regulates monoallelic expression of the <it>IGF2BP1 </it>gene
title_full Allele-specific transcriptional elongation regulates monoallelic expression of the <it>IGF2BP1 </it>gene
title_fullStr Allele-specific transcriptional elongation regulates monoallelic expression of the <it>IGF2BP1 </it>gene
title_full_unstemmed Allele-specific transcriptional elongation regulates monoallelic expression of the <it>IGF2BP1 </it>gene
title_short Allele-specific transcriptional elongation regulates monoallelic expression of the <it>IGF2BP1 </it>gene
title_sort allele specific transcriptional elongation regulates monoallelic expression of the it igf2bp1 it gene
url http://www.epigeneticsandchromatin.com/content/4/1/14
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