Plant chromosomal HMGI/Y proteins and histone H1 exhibit a protein domain of common origin

Krech, Anja B.; Wulff, Dörte; Grasser, Klaus D.; Feix, Günter

doi:10.1016/s0378-1119(99)00067-0

Cited by 23 publications

(21 citation statements)

References 30 publications

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“…Interestingly, a naturally existing domain swap between AT-hooks and H1 CTR occurs in plants, where a globular domain like the one linked to H1 CTR is also found associated with the AT-hook region of plant HMGA (31).…”

Section: Discussionmentioning

confidence: 99%

Functional equivalence of HMGA- and histone H1-like domains in a bacterial transcriptional factor

García‐Heras

Padmanabhan²,

Murillo³

et al. 2009

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

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Section: Discussionmentioning

confidence: 99%

Functional equivalence of HMGA- and histone H1-like domains in a bacterial transcriptional factor

García‐Heras

Padmanabhan²,

Murillo³

et al. 2009

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

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“…Thus, HMGA1 proteins could facilitate global activation of gene expression by relieving histone H1-mediated repression of transcription. Interestingly, the homology of HMGA1 proteins to histone H1 in plants and lower organisms suggest that they evolved from the same protein [141], although their transcriptional regulatory functions have since diverged.…”

Section: Hmga1 Proteins Function In Regulating Gene Expressionmentioning

confidence: 99%

The High Mobility Group A1 (HMGA1) Transcriptome in Cancer and Development

Sumter¹,

Xian²,

Huso³

et al. 2016

CMM

103

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Background & Objectives Chromatin structure is the single most important feature that distinguishes a cancer cell from a normal cell histologically. Chromatin remodeling proteins regulate chromatin structure and high mobility group A (HMGA1) proteins are among the most abundant, nonhistone chromatin remodeling proteins found in cancer cells. These proteins include HMGA1a/HMGA1b isoforms, which result from alternatively spliced mRNA. The HMGA1 gene is overexpressed in cancer and high levels portend a poor prognosis in diverse tumors. HMGA1 is also highly expressed during embryogenesis and postnatally in adult stem cells. Overexpression of HMGA1 drives neoplastic transformation in cultured cells, while inhibiting HMGA1 blocks oncogenic and cancer stem cell properties. Hmga1 transgenic mice succumb to aggressive tumors, demonstrating that dysregulated expression of HMGA1 causes cancer in vivo. HMGA1 is also required for reprogramming somatic cells into induced pluripotent stem cells. HMGA1 proteins function as ancillary transcription factors that bend chromatin and recruit other transcription factors to DNA. They induce oncogenic transformation by activating or repressing specific genes involved in this process and an HMGA1 “transcriptome” is emerging. Although prior studies reveal potent oncogenic properties of HMGA1, we are only beginning to understand the molecular mechanisms through which HMGA1 functions. In this review, we summarize the list of putative downstream transcriptional targets regulated by HMGA1. We also briefly discuss studies linking HMGA1 to Alzheimer’s disease and type-2 diabetes. Conclusion Further elucidation of HMGA1 function should lead to novel therapeutic strategies for cancer and possibly for other diseases associated with aberrant HMGA1 expression.

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“…The ZmHMG I/Y2 protein shares 95% identity with a previously reported maize HMG I/Y sequence ( Fig. 2B) (26). However, the two proteins are likely to be encoded by two different genes since the 5Ј-and 3Ј-UTRs of the ZmHMG I/Y2 cDNA are not fully conserved (40 and 90% identities, respectively) in the corresponding regions of the previously reported maize HMG I/Y cDNA.…”

Section: Structural Features Of Zmhmg I/y2-complete Sequencing Of Thementioning

confidence: 53%

Nickel Resistance and Chromatin Condensation inSaccharomyces cerevisiae Expressing a Maize High Mobility Group I/Y Protein

Forzani

Loulergue

Lobréaux

et al. 2001

Journal of Biological Chemistry

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Numerous metals are essential for living organisms, but they can be toxic when present in excess. A variety of mechanisms, including promotion of oxidative stress and genotoxicity, have been implicated in this toxicity process, and various defense mechanisms have evolved to protect cellular integrity (1). Nickel has been reported to be an essential cofactor for urease in plants (2). Other nickel-binding proteins required for urease activity have recently been reported in soybean (3). However, at high concentrations, nickel ions are very toxic to many organisms, including plants, microorganisms, and mammals.Toxicity due to excess of nickel has been studied in animal systems. Nickel has been described as an allergen and a potent human and rodent carcinogen that induces human respiratory cancers (4). This metal can induce oxidative damages through the production of reactive oxygen species in animal cells, leading to lipid peroxidation, chromosomal deletions, and crosslinking of proteins to DNA (5). However, nickel compounds selectively damage heterochromatic regions, and the major cause of nickel-induced carcinogenicity has been explained by an epigenetic mechanism (6). Nickel compounds would induce an increase in chromatin condensation and methylation, causing neighboring genes, including potential antioncogenes, to be silenced. In Chinese hamster cells, nickel was shown to silence a gpt reporter gene inserted near a dense heterochromatic region susceptible to heterochromatin spreading and silencing (7). This mechanism seems to be conserved in Saccharomyces cerevisiae, in which Broday et al. (8) have shown that nickel can induce silencing of a reporter gene inserted in a telomeric region, involving DNA condensation, independent of methylation.During the last century, soils became enriched with heavy metals as a result of increasing industrial activities (9). Transfer of heavy metals from the soil to the plant may cause both phytotoxic symptoms and the potential accumulation of toxic metals in the edible part of crops. Nickel contamination arose from mining, metal refineries, smelting, sewage sludge, combustion of fuel fossils, and agricultural activities (10). In plants, nickel ions may compete with the uptake of other cations such as Ca 2ϩ , Mg 2ϩ , Fe 2ϩ , and Zn 2ϩ and induce Zn 2ϩ or Fe 2ϩ deficiencies that lead to characteristic plant chlorosis symptoms affecting the photosynthetic activity (11). Mechanisms of nickel resistance in the plant kingdom have been particularly studied using nickel hyperaccumulators, which are plants adapted to nickel-rich soils that accumulate high concentrations of nickel in the shoots without showing any toxicity symptoms. In Alyssum bertolonii, Krä mer et al. (12) have shown that increasing free histidine in the xylem sap enhances translocation of nickel to the shoots, which could explain the metal hyperaccumulating phenotype of this plant. These authors suggested that free histidine may be involved in chelating nickel during the xylem transport. In the aerial parts of plants,...

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Plant chromosomal HMGI/Y proteins and histone H1 exhibit a protein domain of common origin

Cited by 23 publications

References 30 publications

Functional equivalence of HMGA- and histone H1-like domains in a bacterial transcriptional factor

Functional equivalence of HMGA- and histone H1-like domains in a bacterial transcriptional factor

The High Mobility Group A1 (HMGA1) Transcriptome in Cancer and Development

Nickel Resistance and Chromatin Condensation inSaccharomyces cerevisiae Expressing a Maize High Mobility Group I/Y Protein

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