Disease relevance of HMGN2

• Upon i.v. injection, phage displaying this HMGN2 fragment homed to HL-60 and MDA-MB-435 tumors [1].
• 1. Because this region is frequently involved in chromosomal aberrations of various human neoplasms, two PAC clones containing an HMG17 sequence were isolated [2].
• The antimicrobial assays showed that the Escherichia coli-based production of HMGN2 had a potent antimicrobial activity against E. coli ML-35p, Pseudomonas aeruginosa ATCC 27853, and to some extent, against Candida albicans ATCC 10231 [3].
• The antimicrobial assay showed that the MIC of the recombinant holo-HMGN2 against E coli ML-35p (an ampicillin-resistance strain), Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATCC 10231 were 12.5, 25, and 100 mg/L, respectively [4].
• In contrast, recombinant holo-HMGN2 was inactive against Staphylococcus aureus ATCC 25923 [4].

High impact information on HMGN2

• Autoantibodies to nucleosomal proteins: antibodies to HMG-17 in autoimmune diseases [5].
• Chromosomal proteins HMG-14 and HMG-17 are released from mitotic chromosomes and imported into the nucleus by active transport [6].
• Screening phage for binding of progenitor cell-enriched bone marrow cells in vitro, and for homing to HL-60 human leukemia cell xenograft tumors in vivo, yielded a cDNA fragment that encodes an N-terminal fragment of human high mobility group protein 2 (HMGN2, formerly HMG-17) [1].
• A fragment of the HMGN2 protein homes to the nuclei of tumor cells and tumor endothelial cells in vivo [1].
• We conclude that histones and protein HMG-17 are present on transcribed regions of the genome and that passage of RNA polymerase along the chromatin fiber is prevented by antibody binding to these proteins [7].

Biological context of HMGN2

• The human HMGN3 gene is located on chromosome 6 and spans 32 kilobase pairs, which is nearly 10-fold longer than the closely related HMGN2 gene [8].
• Differential phosphorylation of nuclear nonhistone high mobility group proteins HMG 14 and HMG 17 during the cell cycle [9].
• By equilibrium dialysis we demonstrated that acetylation reduces the affinity of HMG-17 to nucleosome cores [10].
• This suggests that HMG 14 or HMG 17 can protect, directly or indirectly, at least an additional 10 base pairs of linker DNA from micrococcal digestion [11].
• However, their nucleotide sequence is significantly different indicating that the multigene family coding for HMG-14 is distinct from that coding for HMG-17 [12].

Anatomical context of HMGN2

• Chromosomal high-mobility-group (HMG) proteins have been examined as substrates for calcium/phospholipid-dependent protein kinase C. Protein kinase C from rat brain phosphorylated efficiently both HMG 14 and HMG 17 derived from calf thymus and the reactions were calcium/phospholipid-dependent [13].
• When in vivo [32P] phosphate labeled HMG proteins from unsynchronized HeLa cells are separated by electrophoresis in acid-urea polyacrylamide gels, as opposed to separation in SDS-polyacrylamide, HMG 17 does not show any 32P incorporation [14].
• Our results indicate that HMG-17 was not phosphorylated in human colon carcinoma cell line HT-29 incubated for 18 h with 32Pi, but that HMG-14a and HMG-14b were phosphorylated [15].
• HMGN2: a novel antimicrobial effector molecule of human mononuclear leukocytes [3]?
• The results suggest that COS cells can tolerate large excess of HMG mRNAs and protein, that the relative amounts of HMG-14 and HMG-17 and their mRNAs are not constant, and that neither the transcription nor the translation of the proteins is coordinately regulated [16].

Associations of HMGN2 with chemical compounds

• The circular dichroism properties of HMG 17 reconstituted highly acetylated and control core chromatin indicated the same alteration of chromatin structure at low ionic strength (1 mM sodium phosphate/0.25 mM EDTA, pH 7.0) [17].
• However, even in this 30-residue long peptide there are significant differences between the proteins as the proline content of HMG-17 (8 residues) is twice that of HMG-14 [18].
• 125I-Labeled HMG 17 was cross-linked to core histones using the protein-protein cross-linking reagent 2-iminothiolane [19].
• Chromosomal proteins HMG-14 and HMG-17. Distinct multigene families coding for similar types of transcripts [18].
• Subsequent perchloric acid extraction of the nuclei, followed by selective acetone precipitation, CM-Sephadex ion exchange chromatography, and gel filtration yielded radioactively labeled high mobility group (HMG) proteins HMG-14 and HMG-17 in pure form [20].

Physical interactions of HMGN2

• Third, by comparing the full-length protein with different domains, we demonstrate that the acidic carboxyl-terminal domain is absolutely required for nucleosome spacing, neither the nucleosome binding domain of HMG 14 or HMG 17 nor the amino-terminal domain plus the nucleosome binding domain of HMG 14 could space nucleosomes [11].
• A large part of exon 8 of the D-PCa-2 gene shows strong similarity to the high-mobility-group nucleosomal binding protein 2 (HMGN2) cDNA [21].

Enzymatic interactions of HMGN2

• In order to definitively determine whether HMG-17 is indeed phosphorylated or whether the protein previously identified as [32P]HMG-17 was a subgroup of HMG-14, we have used the technique of electroblotting in conjunction with an immunochemical procedure utilizing anti-HMG-17 IgG [15].

Regulatory relationships of HMGN2

• In addition, we found that the binding of HMG-14 and HMG-17 to nucleosome cores inhibits the PCAF-mediated acetylation of histone H3 [10].

Other interactions of HMGN2

• Specific acetylation of chromosomal protein HMG-17 by PCAF alters its interaction with nucleosomes [10].
• We describe a newly discovered nuclear protein, HMGN4, that is closely related to the canonical HMGN2 nucleosome-binding protein [22].
• The effect of a high mobility group protein (HMG 17) on the structure of acetylated and control core HeLa cell chromatin [17].
• The functional gene coding for nonhistone chromosomal protein HMG-17, a nucleosomal binding protein that may confer unique properties to the chromatin structure of active genes, has been mapped to band 1p36 [23].
• Chromosomal proteins HMG-14 and HMG-17 are synthesized throughout the S-phase in Burkitt's lymphoma [24].

Analytical, diagnostic and therapeutic context of HMGN2

• Peptide mass and sequence analysis showed major and minor phosphorylation sites, respectively, at Ser24 and Ser28 in HMG-17, and Ser20 and Ser24 in HMG-14 [25].
• By fluorescence in situ hybridization (FISH) on prometaphase spreads, HMG17 was mapped to chromosomal band 1p35 [2].
• The immunocytochemistry staining, enzyme-linked immunosorbent assay, and Western blot revealed that HMGN2 was present in the cytoplasm of mononuclear leukocytes and released to the extracellular environment when stimulated with IL-2 [3].
• Mass spectrometric value and Western blot also indicated its individual character of HMGN2 [3].
• Mobility shift assays with recombinant HMG-17 indicate that synthetic molecules can be used to analyze the interaction of this protein with the nucleosome core [26].

References