HMGN3 belongs to the HMGN family, whose members promote chromatin unfolding, enhance access to nucleosomes, and modulate transcription from chromatin templates []. HMGNs are expressed only in vertebrates []. HMGN3 is highly expressed in the eye and in the brain, where it might play a role in astrocyte function []. In adult pancreatic islet cells, HMGN3 affects both insulin and glucagon levels and modulates the expression of pancreatic genes involved in insulin secretion [].The high mobility group (HMG) proteins are the most abundant and ubiquitous nonhistone chromosomal proteins. They bind to DNA and to nucleosomes and are involved in the regulation of DNA-dependent processes such as transcription, replication, recombination, and DNA repair. They can be grouped into three families: HMGB (HMG 1/2), HMGN (HMG 14/17) and HMGA (HMG I/Y). The characteristic domains are: AT-hook for the HMGA family, the HMG Box for the HMGB family, and the nucleosome-binding domain (NBD) for the members of the HMGN family [].
