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Proteins HMGN ( high mobility group N) form a family of nuclear proteins that bind to nucleosomes , shaping the chromatin structure , enhance transcription and replication of the matrix chromatin . The two protein molecules bind to HMGN independently of nucleosome DNA sequence. This binding also stabilizes the nucleosome stiffening no higher-order chromatin structures . HMGN proteins are part of the architecture of chromatin , facilitating relaxation of chromatin fibers by reducing the inhibitory effect of histones on the transcription process .
During the mitotic fundamental processes in the cell is chromatin condensation and transcriptional inhibition . Both phenomena are due to the removal of many transcription factors , and structural proteins from the chromatin . Changing the way of interaction of chromatin proteins during mitosis often depends on the location and degree of phosphorylation .
During mitosis HMGN protein phosphorylation are subject to storage , modification affects an evolutionarily conserved domain deciding on the binding of these proteins to the nucleosome (NBD - nucleosomal binding domain) . It has been shown that phosphorylation inhibits the binding domains of proteins NBD HMGN of a nucleosome , and negatively affect their transport to the nucleus when the nuclear membrane reconstitution late telophase . As a result of the lowering of the phosphorylation of the nucleosome HMGN affinity , which is caused by the change of the negative charge of protein , while the inhibition of transport to the nucleus is associated with the presence of a phosphate group , which determines the specific interaction of proteins with certain HMGN 14-3-3 protein isoforms . It has been shown that there is a close relationship between the effects of HMGN with chromatin , and their transport into the nucleus . Mitotic phosphorylation affects both the two processes , thus controlling the accessibility of chromatin proteins HMGN .

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The Editorial Board
Andrzej Łukaszyk - przewodniczący, Zofia Bielańska-Osuchowska, Szczepan Biliński, Mieczysław Chorąży, Aleksander Koj, Włodzimierz Korochoda, Leszek Kuźnicki, Aleksandra Stojałowska, Lech Wojtczak

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