High impact information on HMG2

• Monoclonal antibodies specific for the non-histone chromosomal protein HMG17 were used to isolate oligonucleosomes from the transcriptionally active chromatin of chicken liver and oviduct [1].
• Most of this sensitivity persists when histone H1 and most of the non-histone chromosomal proteins are removed with 0.6 M NaCl [2].
• HMG-14 and HMG-17 form a family of ubiquitous non-histone chromosomal proteins and have been reported to bind preferentially to regions of active chromatin structure [3].
• HMG2b is the major HMG2 subtype in testis and reaches the highest proportion, detected so far, in spermatid cells obtained by centrifugal elutriation [4].
• In conclusion, the pattern of HMG2 composition is different in three quiescent and terminally differentiated cell types, no correlation between the state of cell proliferation and HMG2 composition can be established [4].

Biological context of HMG2

• The ratios HMG1/nucleosomal histone and HMG2/nucleosomal histone increased markedly at the end of spermiogenesis during the transition from nucleohistone to nucleoprotamine when nucleosomes are being disassembled [5].
• The stimulation, by a change of medium, of the proliferation of dense cultures of normal chick fibroblasts also induced an increase in the kinase activity and endogenous phosphorylation of NHC proteins [6].
• Low molar ratios of HMG 2 were found to be sufficient for complete inhibition of S1 cleavage of a supercoiled plasmid containing the globin gene [7].

Anatomical context of HMG2

• The ratio HMG1/HMG2 remained constant (0.66 +/- 0.04) during the transition from dividing meiotic and premeiotic cells to nondividing spermatids and from transcriptionally active cells (spermatogonia, spermatocytes and early spermatids) to transcriptionally inactive late spermatids [5].
• The high mobility group chromosomal proteins HMG1 and HMG2 were not detectable in the nuclei of rooster spermatozoa [5].
• In glandular stomach, liver and spleen, the relative contents of both HMG-1 and HMG-2 are markedly lower than in thymus and Bursa Fabricii [8].
• The primary structure of non-histone chromosomal protein HMG17 from chicken erythrocyte nuclei [9].
• A small RNA found in the fraction on non-histone chromosomal proteins or rat liver and chicken reticulocytes [Holoubek, V., Deacon, N.J., Buckle, D.W. and Naora, H. (1983) Eur. J. Biochem. 137, 249-256] has been isolated from rat liver and then sequenced [10].

Associations of HMG2 with chemical compounds

• Cross-linking with a 'zero-length' cross-linker 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and with a longer (cleavable) cross-linker dimethyl-3,3'-dithiobispropionimidate revealed an interaction of HMG1 and HMG2 with (or proximity to) core histones in both types of particles [11].
• Under low ionic conditions (2 mM Tris buffer plus EDTA) addition of 1-2 molecules of HMG2 per nucleosome markedly stabilized the segment of the linker DNA against thermal denaturation [12].
• 2. The percent of phosphotyrosine residues in NHC proteins was clearly increased when the proteins were extracted from transformed cells instead of normal cells [6].
• Quantitative analysis of non-histone chromosomal proteins HMG 14 and HMG 17 by polyacrylamide gel electrophoresis [13].
• Interaction of calf thymus non-histone chromosomal protein HMG2 with H1,H5-depleted nucleosomes from chicken erythrocytes was studied by means of thermal denaturation and an N-(3-pyrene)maleimide fluorescence probe [12].

Other interactions of HMG2

• This suggested that the amount of non-histone chromosomal protein does not play an important role in the sensitivity of chromatin DNA to nuclease digestion [14].
• Binding of non-histone chromosomal protein HMG1 to histone H3 in nucleosomes detected by photochemical cross-linking [15].

References