Preferential affinity of high molecular weight high mobility group non-histone chromatin proteins for single-stranded DNA.

Isackson, Paul J.; Fishback, James L.; Bidney, Dennis; Reeck, Gerald R.

doi:10.1016/s0021-9258(18)50445-2

Cited by 141 publications

(18 citation statements)

References 20 publications

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“…Whether certain subsets of the HMG proteins 1 and 2, and the homologous protein HMG-T of trout testis, are specifically associated with replicating and/or transcribable regions ofchromatin is so far not clear. Whereas some authors have reported a specific association with "active" chromatin fractions obtained from various cell types and species (15,(21)(22)(23)(24), other authors could not confirm this observation (25,26). There is no doubt, however, that proteins HMG-1 and -2 are also integral components of chromatin.…”

mentioning

confidence: 94%

High mobility group proteins of amphibian oocytes: a large storage pool of a soluble high mobility group-1-like protein and involvement in transcriptional events.

Kleinschmidt¹,

Scheer²,

Dabauvalle³

et al. 1983

The Journal of Cell Biology

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Oocytes of several amphibian species (Xenopus laevis, Rana temporaria, andPleurodeles waltlii) contained a relatively large pool of nonchromatin-bound, soluble high mobility group (HMG) protein with properties similar to those of calf thymus proteins HMG-1 and HMG-2 (protein HMG-A; A, amphibian). About half of this soluble HMG-A was located in the nuclear sap, the other half was recovered in enucleated ooplasms. This protein was identified by its mobility on one-and two-dimensional gel electrophoresis, by binding of antibodies to calf thymus HMG-1 to polypeptides electrophoretically separated and blotted on nitrocellulose paper, and by tryptic peptide mapping of radioiodinated polypeptides. Most, if not all, of the HMG-A in the soluble nuclear protein fraction, preparatively defined as supernatant obtained after centrifugation at 100,000 g for 1 h, was in free monomeric form, apparently not bound to other proteins. On gel filtration it eluted with a mean peak corresponding to an apparent molecular weight of ,-25,000; on sucrose gradient centrifugation it appeared with a very low S value (2-3 S), and on isoelectric focusing it appeared in fractions ranging from pH ~7 to 9. This soluble HMG-A was retained on DEAE-Sephacel but could be eluted already at moderate salt concentrations (0.2 M KCI). In oocytes of various stages of oogenesis HMG-A was accumulated in the nucleus up to concentrations of ~14 ng per nucleus (in Xenopus), corresponding to --0.2 mg/ml, similar to those of the nucleosomal core histones. This nuclear concentration is also demonstrated using immunofluorescence microscopy. When antibodies to bovine HMG-1 were microinjected into nuclei of living oocytes of Pleurodeles the lateral loops of the lampbrush chromosomes gradually retracted and the whole chromosomes condensed. As shown using electron microscopy of spread chromatin from such injected oocyte nuclei, this process of loop retraction was accompanied by the appearance of variously-sized and irregularly-spaced gaps within transcriptional units of chromosomal loops but not of nucleoli, indicating that the transcription of non-nucleolar genes was specifically inhibited by this treatment and hence involved an HMG-l-like protein.These data show that proteins of the HMG-1 and -2 category, which are usually chromatinbound components, can exist, at least in amphibian oocytes, in a free soluble monomeric form, apparently not bound to other molecules. The possible role of this large oocyte pool of soluble HMG-A in early embryogenesis is discussed as well as the possible existence of soluble HMG proteins in other cells.The high mobility group (HMG) I proteins are a family of Abbreviations used in thispaper: HMG, high mobility group; PCA, perchloric acid; TCA, trichloroacetic acid. 838 nonhistone components of chromatin that are of relatively low molecular weight (Mr 7,000), contain high proportions of both positively and negatively charged residues distributed in a polar fashion, can be extracted from chro-

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mentioning

confidence: 94%

High mobility group proteins of amphibian oocytes: a large storage pool of a soluble high mobility group-1-like protein and involvement in transcriptional events.

Kleinschmidt¹,

Scheer²,

Dabauvalle³

et al. 1983

The Journal of Cell Biology

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“…Each individual HMG box can bind to DNA in a manner that is not sequence specific but is sensitive to the structure of the DNA [14]. The proteins show an increased affinity for non-B form distorted DNA structures (illustrated in Figure 1B), such as cisplatinated DNA [22], cruciform DNA [23], single stranded DNA [24], supercoiled DNA [25], hemi catenated DNA [26], and DNA mini circles [27]. Moreover, atypical DNA structures can form in cells and play a role in regulating genomic processes through interactions with architectural and regulatory proteins [28,29].…”

Section: The Hmgb Proteins Bind Diverse Dna Structures and Interact With Histone Proteinsmentioning

confidence: 99%

Interactions of HMGB Proteins with the Genome and the Impact on Disease

2021

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High Mobility Group Box (HMGB) proteins are small architectural DNA binding proteins that regulate multiple genomic processes such as DNA damage repair, nucleosome sliding, telomere homeostasis, and transcription. In doing so they control both normal cellular functions and impact a myriad of disease states, including cancers and autoimmune diseases. HMGB proteins bind to DNA and nucleosomes to modulate the local chromatin environment, which facilitates the binding of regulatory protein factors to the genome and modulates higher order chromosomal organization. Numerous studies over the years have characterized the structure and function of interactions between HMGB proteins and DNA, both biochemically and inside cells, providing valuable mechanistic insight as well as evidence these interactions influence pathological processes. This review highlights recent studies supporting the roles of HMGB1 and HMGB2 in global organization of the genome, as well as roles in transcriptional regulation and telomere maintenance via interactions with G-quadruplex structures. Moreover, emerging models for how HMGB proteins function as RNA binding proteins are presented. Nuclear HMGB proteins have broad regulatory potential to impact numerous aspects of cellular metabolism in normal and disease states.

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“…Since then HMG1/2 box sequences have been identified in more than 150 proteins (3)(4)(5)(6), including transcription factors and DNA repair proteins. Substrates for HMG1/2 proteins include single-stranded (ss)DNA (7), duplexes containing AT sequences (8), supercoiled DNA (9) and branched or cruciform DNAs (10,11). The molecular structures of HMG boxes from several members of the family have been determined, revealing a common flattened triangular fold formed by intersection of three helical arms (12)(13)(14)(15).…”

Section: Introductionmentioning

confidence: 99%

DNA binding by single HMG box model proteins

Hong

Taudte

Kallenbach³

et al. 2000

Nucleic Acids Research

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The HMG1/2 family is a large group of proteins that share a conserved sequence of approximately 80 amino acids rich in basic, aromatic and proline side chains, referred to as an HMG box. Previous studies show that HMG boxes can bind to DNA in a structure-specific manner. To define the basis for DNA recognition by HMG boxes, we characterize the interaction of two model HMG boxes, one a structure-specific box, rHMGb from the rat HMG1 protein, the other a sequence-specific box, Rox1 from yeast, with oligodeoxynucleotide substrates. Both proteins interact with single-stranded oligonucleotides in this study to form 1:1 complexes. The stoichiometry of binding of rHMGb to duplex or branched DNAs differs: for a 16mer duplex we find a weak 2:1 complex, while a 4:1 protein:DNA complex is detected with a four-way DNA junction of 16mers in the presence of Mg(2+). In the case of the sequence-specific Rox1 protein we find tight 1:1 and 2:1 complexes with its cognate duplex sequence and again a 4:1 complex with four-way branched DNA. If the DNA branching is reduced to three arms, both proteins form 3:1 complexes. We believe that these multimeric complexes are relevant for HMG1/2 proteins in vivo, since Mg(2+) is present in the nucleus and these proteins are expressed at a very high level.

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Preferential affinity of high molecular weight high mobility group non-histone chromatin proteins for single-stranded DNA.

Cited by 141 publications

References 20 publications

High mobility group proteins of amphibian oocytes: a large storage pool of a soluble high mobility group-1-like protein and involvement in transcriptional events.

High mobility group proteins of amphibian oocytes: a large storage pool of a soluble high mobility group-1-like protein and involvement in transcriptional events.

Interactions of HMGB Proteins with the Genome and the Impact on Disease

DNA binding by single HMG box model proteins

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