Disease relevance of Hmgb2

• Loss of chromosomal high mobility group proteins HMG1 and HMG2 when mouse neuroblastoma and Friend erythroleukemia cells become committed to differentiation [1].
• Conservation of chromosomal high mobility group proteins HMG1 and HMG2 during differentiation of mouse myeloid leukemia cells [2].

High impact information on Hmgb2

• A chimeric protein, in which the strong transactivation domain of VP16 was fused directly to the HMG domains of HMG2, stimulated the activity of an octamer-dependent reporter construct upon cotransfection [3].
• Comparative studies on microinjected high-mobility-group chromosomal proteins, HMG1 and HMG2 [4].
• However, in calf thymus, HMG1 and HMG2 molecules appeared in the 0.35 M NaCl extract of isolated nuclei, as expected [4].
• Both injected and endogenous HMG1 and HMG2 partitioned unexpectedly upon fractionation of bovine fibroblasts, HeLa, or 3T3 cells, appearing in the cytoplasmic fractions [4].
• We show that in adult mice Hmgb2 is restricted mainly to lymphoid organs and testes, although it is widely expressed during embryogenesis [5].

Biological context of Hmgb2

• Reduced fertility and spermatogenesis defects in mice lacking chromosomal protein Hmgb2 [5].
• This peculiar pattern of expression and the phenotype of mutants indicate that Hmgb2 has a specialised role in germ cell differentiation [5].
• Nucleotide sequence of a mouse cDNA encoding the non-histone chromosomal high mobility group protein-2 (HMG-2) [6].
• The expression of reporter genes transfected into the cells was enhanced approximately 2-fold in cells overexpressing HMG1, but not HMG2, in comparison with those in control cells, irrespective of the sources of the genes and promoters [7].
• The minichromosome derived from the reporter plasmid in cells overexpressing HMG1 protein was more susceptible to micrococcal nuclease digestion than those in cells overexpressing HMG2 protein and control cells [7].

Anatomical context of Hmgb2

• Significantly, Hmgb2 is expressed at very high levels in primary spermatocytes, while it is barely detectable in spermatogonia and elongated spermatids [5].
• Limited digestion of fetal calf thymus nuclei with DNase I led to the solubilization of a substantial fraction of proteins HMG-1 and HMG-2 together with smaller amounts of H1 [8].
• In addition, HMG1 and HMG2 did not differ in their partitioning upon fractionation nor in their stability in growing vs. nongrowing 3T3 cells [4].
• High mobility group 2 (HMG2) protein is ubiquitously distributed in the nucleus of higher eukaryotic cells [9].
• Accumulation of an HMG2-beta-galactosidase fusion protein expressed in COS-7 cells suggested active transport of HMG2 protein into the nucleus after translation in the cytoplasm [9].

Associations of Hmgb2 with chemical compounds

• This soluble (S) fraction was relatively depleted in H1 histones and methylated DNA (5-methylcytosine) but highly enriched in RNA, single-stranded DNA, and nonhistone chromosomal proteins, particularly two species of the high mobility group identified as HMG 1 and HMG 2 [10].
• Ten of thirteen species showed a rapidly migrating HMG2 subtype in testis tissue, separable by acid/urea/polyacrylamide-gel electrophoresis [11].
• The results of northern blot analysis for small proline-rich protein 2 (Sprr2), 17beta-hydroxysteroid dehydrogenase type 2 (17betaHSD-2), high mobility group 2 (Hmg2), mitotic checkpoint component 2 (Mad2) and an EST AW555366 mRNA were consistent with that of microarray analysis [12].

Other interactions of Hmgb2

• CLEBP-1 and closely related HMG-1 and HMG-2 proteins may play key roles in facilitating the expression of the lymphokine genes that contain CLE0 elements [13].
• The relative amounts of two other low-Mr HMG proteins HMG 14 and HMG 17 remained essentially unchanged and only a minor decrease was observed in the content of one of the high-Mr HMG proteins, HMG 2 [14].

Analytical, diagnostic and therapeutic context of Hmgb2

• Interestingly, the HMG2 protein is not present in the protein-DNA complex detected by an electrophoretic mobility shift assay [3].
• Thus, we have not detected any significant differences in the intracellular behavior of HMG1 and HMG2 after microinjection into human, bovine, or murine cells [4].
• Circular dichroism, thermal denaturation, and deoxyribonuclease I digestion studies of nucleosomes highly enriched in high mobility group proteins HMG 1 and HMG 2 [15].

References