Homodimers of Chromosomal Proteins HMG-14 and HMG-17 in Nucleosome Cores

Postnikov, Yuri V.; Trieschmann, Lothar; Rickers, Anke; Bustin, Michael

doi:10.1006/jmbi.1995.0508

Cited by 57 publications

(59 citation statements)

References 23 publications

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“…The feasibility of an interaction between histone H1 and HMG-14 or HMG-17 is suggested by the overlap of binding sites of HMG-14 and HMG-17 with that of histone H1 near the dyad axis of the nucleosome (2). Third, HMG-14 may interact directly with only the core nucleosome, altering its configuration in subtle ways (50,64) either to modify its interactions with histone H1 or to inhibit its ability to stack onto adjacent nucleosomes. These three models are clearly not mutually exclusive.…”

Section: Discussionmentioning

confidence: 99%

Alleviation of Histone H1-Mediated Transcriptional Repression and Chromatin Compaction by the Acidic Activation Region in Chromosomal Protein HMG-14

Ding

Bustin

Hansen

1997

Molecular and Cellular Biology

114

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Histone H1 promotes the generation of a condensed, transcriptionally inactive, higher-order chromatin structure. Consequently, histone H1 activity must be antagonized in order to convert chromatin to a transcriptionally competent, more extended structure. Using simian virus 40 minichromosomes as a model system, we now demonstrate that the nonhistone chromosomal protein HMG-14, which is known to preferentially associate with active chromatin, completely alleviates histone H1-mediated inhibition of transcription by RNA polymerase II. HMG-14 also partially disrupts histone H1-dependent compaction of chromatin. Both the transcriptional enhancement and chromatin-unfolding activities of HMG-14 are mediated through its acidic, C-terminal region. Strikingly, transcriptional and structural activities of HMG-14 are maintained upon replacement of the C-terminal fragment by acidic regions from either GAL4 or HMG-2. These data support the model that the acidic C terminus of HMG-14 is involved in unfolding higher-order chromatin structure to facilitate transcriptional activation of mammalian genes.In mammalian cells, genomic DNA is highly condensed, being organized in the nucleoprotein complex constituting chromatin (65,70). The packaging of genomic DNA into chromatin can inhibit gene expression in multiple ways: restricting the access of transcription factors to their promoter elements, blocking assembly and initiation by the general transcriptional machinery, and inhibiting elongation by the RNA polymerase. As a corollary, activation of transcription requires remodeling of the chromatin structure of the gene in order to relieve the repressive effects of chromatin on transcription (34,38,45,71,72).The building block of chromatin is the nucleosome, consisting of DNA wrapped twice around a histone octamer comprising the core histones H2A, H2B, H3, and H4. A linker histone, generally histone H1, interacts with DNA at several sites simultaneously (3, 51, 55, 58): (i) with DNA at or close to the entry and exit points of the nucleosome, (ii) with nucleosomal DNA over the dyad axis, after one wrap around the octamer, and (iii) with linker DNA between adjacent nucleosomal core particles. Within the interphase nucleus of higher eukaryotic cells, the linear array of nucleosomes is folded into a higherorder structure, called the 30-nm chromatin fiber (65, 70). Histone H1 plays a key role in the formation of such a higherorder chromatin structure (4, 37, 52, 59, 60).Biochemical and genetic studies have identified two distinct systems capable of remodeling the nucleosome structure for transcriptional activation. The multisubunit SWI/SNF complex, which is conserved from yeasts to humans (49, 69), can perturb the structure of a nucleosome in an ATP-dependent manner (15,29,35). This promotes the binding in vitro of either specific or general transcription factors, such as GAL4 and TBP, to their sites on nucleosomal DNA. A distinct nucleosome-remodeling factor (NURF), originally purified from Drosophila embryo extracts (63), is also capable ...

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Section: Discussionmentioning

confidence: 99%

Alleviation of Histone H1-Mediated Transcriptional Repression and Chromatin Compaction by the Acidic Activation Region in Chromosomal Protein HMG-14

Ding

Bustin

Hansen

1997

Molecular and Cellular Biology

114

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“…Anti-␤-actin mouse monoclonal, catalog #A5316 clone AC-74, anti-human HMGN1 (62,63), and anti-mouse HMGN1 (peptide 6) (12, 64) were from Sigma. ChIP sequence analysis of CD4ϩ human T cells was performed as described (22).…”

Section: Methodsmentioning

confidence: 99%

The Chromatin-binding Protein HMGN1 Regulates the Expression of Methyl CpG-binding Protein 2 (MECP2) and Affects the Behavior of Mice

Abuhatzira

Shamir

Schones

et al. 2011

Journal of Biological Chemistry

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Background: HMGN1 is a chromatin-binding protein that modulates the cellular transcription profile. Results: Mice that either overexpress or lack HMGN1 have altered behavioral phenotypes. HMGN1 is a negative regulator of MeCP2, a protein involved in neurodevelopmental disorders. Conclusion: Misregulation of HMGN1 protein levels lead to behavioral changes in mice. Significance: HMGN1 is an epigenetic factor that contributes to the development of neurodevelopmental disorders.

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“…Accordingly, the addition of an equimolar mixture of HMGN1 and HMGN2 to CPs resulted in complexes that contained one CP and two molecules of either HMGN1 or HMGN2. CP complexes that contained one molecule of HMGN1 and one of HMGN2 were not detected (29). Likewise, the addition of HMGN2 and mHMGN5 to purified CPs resulted in complexes that contained either two molecules of HMGN2 or two molecules of mHMGN5 (34).…”

Section: Hmgn5 Is a Rapidly Evolving Proteinmentioning

confidence: 96%

Distinct Properties of Human HMGN5 Reveal a Rapidly Evolving but Functionally Conserved Nucleosome Binding Protein

Malicet

Rochman

Postnikov

et al. 2011

Molecular and Cellular Biology

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The HMGN family is a family of nucleosome-binding architectural proteins that affect the structure and function of chromatin in vertebrates. We report that the HMGN5 variant, encoded by a gene located on chromosome X, is a rapidly evolving protein with an acidic C-terminal domain that differs among vertebrate species. We found that the intranuclear organization and nucleosome interactions of human HMGN5 are distinct from those of mouse HMGN5 and that the C-terminal region of the protein is the main determinant of the chromatin interaction properties. Despite their apparent differences, both mouse and human HMGN5 proteins interact with histone H1, reduce its chromatin residence time, and can induce large-scale chromatin decompaction in living cells. Analysis of HMGN5 mutants suggests that distinct domains in HMGN5 affect specific steps in the interaction of H1 with chromatin. Elevated levels of either human or mouse HMGN5 affect the transcription of numerous genes, most in a variant-specific manner. Our study identifies HMGN5 as a rapidly evolving vertebrate nuclear protein with species-specific properties. HMGN5 has a highly disordered structure, binds dynamically to nucleosome core particles, modulates the binding of H1 to chromatin, reduces the compaction of the chromatin fiber, and affects transcription.

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Homodimers of Chromosomal Proteins HMG-14 and HMG-17 in Nucleosome Cores

Cited by 57 publications

References 23 publications

Alleviation of Histone H1-Mediated Transcriptional Repression and Chromatin Compaction by the Acidic Activation Region in Chromosomal Protein HMG-14

Alleviation of Histone H1-Mediated Transcriptional Repression and Chromatin Compaction by the Acidic Activation Region in Chromosomal Protein HMG-14

The Chromatin-binding Protein HMGN1 Regulates the Expression of Methyl CpG-binding Protein 2 (MECP2) and Affects the Behavior of Mice

Distinct Properties of Human HMGN5 Reveal a Rapidly Evolving but Functionally Conserved Nucleosome Binding Protein

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