HMGN2 (D9B9) XP^® Rabbit mAb #9437

High mobility group (HMG) proteins are a superfamily of abundant and ubiquitous nuclear proteins that bind DNA without sequence specificity and induce structural changes to the chromatin fiber to regulate access to the underlying DNA. The HMGN family of proteins, which includes five members (HMGN1-5), is characterized by the presence of several conserved protein domains: a positively charged domain, a nucleosome binding domain, and an acidic C-terminal chromatin-unfolding domain (1,2). HMGN proteins function in transcriptional regulation and are recruited to gene promoters by transcription factors, such as estrogen receptor α (ERα), serum responsive factor (SRF), and PITX2, where they can facilitate either gene activation or repression (3-5). HMGN proteins bind specifically to nucleosomal DNA and reduce compaction of the chromatin fiber, in part by competing with linker histone H1 for nucleosome binding (6). In addition, HMGN proteins act to modulate local levels of post-translational histone modifications, decreasing phosphorylation of histone H3 at Ser10 and histone H2A at Ser1 and increasing acetylation of histone H3 at Lys14 (7-9). HMGN proteins can also modulate the activity of several chromatin-remodeling factors and restrict nucleosome mobility (10).
HMGN2 (also known as HMG17) expression is tightly linked to cellular differentiation. HMGN2 is ubiquitous and highly expressed in all embryonic tissues. During mouse embryogenesis, expression is down-regulated throughout the embryo, except in committed, continuously renewing cell types undergoing active differentiation, such as the basal layer of the epithelium and kidney cells undergoing mesenchyme to epithelium transition (11,12). In addition to its function in regulating chromatin structure in the nucleus, HMGN2 also plays a role in innate immunity against bacterial pathogens and tumor cells. Leukocytes, which play a central role in the innate immune defense in mammals by secreting an array of antimicrobial proteins and peptides, secrete HMGN2 upon stimulation with interleukin 2 (IL-2). Following stimulation, HMGN2 translocates from the nucleus to the cytoplasm and is released into the extracellular environment (13). HMGN2, more specifically the alpha-helical domain (residues 18 to 48), shows strong antimicrobial activity towards multiple bacterial pathogens (13). In addition, the amino-terminus of HMGN2 has been shown to contain tumor homing activity, while the carboxy-terminal region inhibits tumor invasion and metastasis (14,15).