The effect of histone H1 and DNA methylation on transcription

Johnson, Colin A.; Goddard, John P.; Adams, Roger

doi:10.1042/bj3050791

Cited by 41 publications

(20 citation statements)

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“…It follows that the preferential inhibition of transcription from the methylated template seen in their study could result from the weakness of the methylated promoter, rather than discriminatory binding by H1. It is not known whether the factors responsible for driving transcription of the tRNA gene in the study by Johnson et al (27) are directly affected by methylation.…”

Section: Discussionmentioning

confidence: 95%

“…The activity, known as MDBP-2, was originally identified as a 40-kDa protein that was very tissue specific in distribution (26) but was subsequently attributed to a dimer of H1 (25). Finally, Johnson et al (27) have concluded that H1 preferentially inhibits transcription from a methylated template, and they propose that methylated sites on the DNA serve as foci for long range chromatin condensation mediated by H1.…”

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confidence: 99%

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Binding of Histone H1 to DNA Is Indifferent to Methylation at CpG Sequences

Campoy

Meehan

McKay

et al. 1995

Journal of Biological Chemistry

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The possibility that histone H1 binds preferentially to DNA containing 5-methylcytosine in the dinucleotide CpG is appealing, as it could help to explain the repressive effects of methylation on gene activity. In this study, the affinity of purified H1 for methylated and non-methylated DNA sequences has been tested using both naked DNA and chromatin. Based on a variety of assays (bandshifts, filter-binding assays, Southwestern blots, and nuclease sensitivity assays), we conclude that H1 has no significant preference for binding to naked methylated DNA. Similarly, H1 showed the same affinities for methylated and non-methylated DNA when assembled into chromatin in a Xenopus oocyte extract. Thus potential cooperative interaction of H1 with polynucleosomal complexes is not enhanced by the presence of DNA methylation.The major DNA modification in vertebrates is methylation at the 5 position of cytosine in the dinucleotide CpG. About 60 -90% of genomic CpGs contain 5-methyl cytosine (m 5 C). Transfection assays with methylated genes have shown that CpG methylation often causes repression of transcription (1-4). The severity of repression depends on a number of parameters, particularly the location of methylation relative to the promoter (1, 5; but see Ref. 6), the local density of methyl-CpG pairs, and the strength of the promoter under test (7). In general, high density methylation strongly inhibits transcription, whereas low density methylation can only inhibit weak promoters.Several lines of evidence suggest that proteins that bind preferentially to methylated DNA are important components of the repression mechanism. Indeed, binding of the methyl-CpGbinding protein (MeCP) 1 MeCP1 (8) shows the same dependence on local density of methylation as does transcriptional repression (4, 7). Methylation-associated transcriptional repression may also arise by other routes. CpG methylation is known to prevent binding of some transcription factors, and this is likely to contribute to repression in some cases (9, 10). Another potential cause of methylation-mediated repression is direct alteration of chromatin structure due to the presence of m 5 C. Involvement of chromatin in mediating the effects of DNA methylation is suggested by the experiments of Buschhausen et al. (3,11). In addition, Keshet et al. found that methylated DNA is preferentially assembled into nuclease-resistant chromatin after transfection (12). While these results could be explained by interaction between known methyl-CpG-binding proteins and chromatin, it is also possible that an ubiquitous component of chromatin, for example histones, interacts differentially with methylated DNA leading to an altered higher order structure that is incompatible with gene expression.Attempts to detect an effect of DNA methylation on nucleosomal cores have not been successful (13,14). The linker histone H1, however, is an attractive candidate for mediator of the effects of methylation on chromatin. H1 plays a role in chromatin condensation (15, 16). It is depleted in CpG i...

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Section: Discussionmentioning

confidence: 95%

mentioning

confidence: 99%

Binding of Histone H1 to DNA Is Indifferent to Methylation at CpG Sequences

Campoy

Meehan

McKay

et al. 1995

Journal of Biological Chemistry

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“…These results suggest a direct, site-speci®c eect of methylation on transcriptional activation. However, CpG methylation may also exert an indirect eect on the accessibility of DNA to protein factors, since the nucleosomal organization of transcription factor binding sites implies a role for chromatin structure in determining DNA accessibility (Ben-Hattar et al, 1989;Weih et al, 1991;Johnson et al, 1995). In either case, the high density of CpGs within putative BRCA1 regulatory elements represents a considerable target at which DNA methylation can either directly or indirectly exert a functional eect (Figure 6).…”

Section: Discussionmentioning

confidence: 99%

CpG methylation within the 5′ regulatory region of the BRCA1 gene is tumor specific and includes a putative CREB binding site

et al. 1998

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Breast cancer is a genetic disease arising from a series of germ-line and/or somatic DNA changes in a variety of genes, including BRCA1 and BRCA2. DNA modi®ca-tions have been shown to occur by a number of mechanisms that include DNA methylation. In some cases, the aberrant methylation of CpGs within 5' regulatory regions has led to suppression of gene activity. In this report we describe a variation in the pattern of DNA methylation within the regulatory region of the BRCA1 gene. We found no evidence of methylation at CpGs within the BRCA1 promoter in a variety of normal human tissues. However, screening of a series of randomly sampled breast carcinomas revealed the presence of CpG methylation adjacent to the BRCA1 transcription start site. One such methylated CpG occurs at a putative CREB (cAMP-responsive element binding) transcription factor binding site in the BRCA1 promoter. Gelshift assays with methylated and unmethylated BRCA1/CREB binding site oligonucleotides demonstrate that this site is sensitive to site-speci®c CpG methylation. These data suggest that aberrant DNA methylation at regulatory sequences in the BRCA1 locus may play a role in the transcriptional inactivation of the BRCA1 gene within subclones of breast tumors. This study represents the ®rst evidence suggesting a role for DNA methylation in the transcriptional inactivation of the BRCA1 in human breast cancer.

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“…Subsequently purified MDBP2 was found to be histone H1 (34). Though some investigators have proposed preferential binding of histone H1 to methylated DNA and thereby implicated it in methylation-mediated transcriptional repression (35,36), others have found this not to be the case (37). MeCP-1 binds in vitro to DNA containing at least 12 symmetrically methylated CpGs (20), whereas MeCP-2 can bind to a single methylated CpG (31).…”

Section: Methylation Of Whole Plasmid or 22-kb Upstream Promoter Butmentioning

confidence: 99%

Methylation of the minimal promoter of an embryonic globin gene silences transcription in primary erythroid cells

Singal

Ferris

Little

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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Methylation of cytosines in the dinucleotide CpG has been shown to suppress transcription of a number of tissue-specific genes, yet the precise mechanism is not fully understood. The vertebrate globin genes were among the first examples in which an inverse correlation was shown between CpG methylation and transcription. We studied the methylation pattern of the 235-bp -globin gene promoter in genomic DNA from primary chicken erythroid cells using the sodium bisulfite conversion technique and found all CpGs in the promoter to be methylated in erythroid cells from adult chickens in which the -globin gene is silent but unmethylated in 5-day (primitive) embryonic red cells in which the gene is transcribed. To elucidate further the mechanism of methylation-induced silencing, an expression construct consisting of 235 bp of 5 promoter sequence of the -globin gene along with a strong 5 erythroid enhancer driving a chloramphenicol acetyltransferase reporter gene, -CAT, was transfected into primary avian erythroid cells derived from 5-day embryos. Methylation of just the 235-bp -globin gene promoter fragment at every CpG resulted in a 20-to 30-fold inhibition of transcription, and this effect was not overridden by the presence of potent erythroid-specific enhancers. The ability of the 235-bp -globin gene promoter to bind to a DNA Methyl Cytosine binding Protein Complex (MeCPC) was tested in electrophoretic mobility shift assays utilizing primary avian erythroid cell nuclear extract. The results were that fully methylated but not unmethylated 235-bp -globin gene promoter fragment could compete efficiently for MeCPC binding. These results are a direct demonstration that site-specific methylation of a globin gene promoter at the exact CpGs that are methylated in vivo can silence transcription in homologous primary erythroid cells. Further, these data implicate binding of MeCPC to the promoter in the mechanism of silencing.Methylation of cytosine residues in the dinucleotide CpG is the most common postsynthetic eukaryotic DNA modification. Since the reports of an inverse correlation between DNA methylation and expression of vertebrate ␤-type globin genes (1-3), a large body of evidence relating DNA methylation to gene expression has accumulated (4, 5). At the same time, the absence of detectable DNA methylation in some eukaryotes such as Drosophila (6) and Saccharomyces cerevisiae (7) has raised doubts about its role in normal development and tissue-specific gene expression. However a study by Li et al. (8) showing abnormal development and embryonic lethality in transgenic mice expressing decreased but not completely absent DNA methyl transferase activity following knockout of the DNA methyl transferase gene lends strong support to a critical role for DNA methylation in developmental gene regulation. Recently, a similar critical function of DNA methylation in plant development has been demonstrated by Ronemus et al. (9). However, a direct demonstration of the role of DNA methylation in suppressing transcription of a...

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The effect of histone H1 and DNA methylation on transcription

Cited by 41 publications

References 50 publications

Binding of Histone H1 to DNA Is Indifferent to Methylation at CpG Sequences

Binding of Histone H1 to DNA Is Indifferent to Methylation at CpG Sequences

CpG methylation within the 5′ regulatory region of the BRCA1 gene is tumor specific and includes a putative CREB binding site

Methylation of the minimal promoter of an embryonic globin gene silences transcription in primary erythroid cells

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