Histone H1

• OMIM: 142708

• MGI: 95893

Histone H1 is a protein found in the cell nucleus. It is one of the five main histone proteins of the chromatin in eukaryotic cells. In addition to its function as a scaffold for the DNA double strand, it plays a role in transcription. There are at least six variants of the H1, designated with H1.1 to H1.5 and H10. Except in simple organisms such as baker's yeast, all variants are found in animals and plants.

Biosynthesis

In humans, the gene for the variant H1 ( 0) is located on chromosome 22, all other versions are to be found in a group on chromosome 6. From the translation product in each case the start methionine is cleaved. The length and the molecular weight of the resulting protein can be read from the table.

Biological Function

Histone H1 marks the position at which the DNA wraps around the Histonoctamer. In the G1 phase of the cell cycle the phosphorylation of the protein begins and proceeds to the end of the cell, however, is not evenly distributed over the nucleus; it is believed that active (strongly transcribed ) genes and a high degree of phosphorylation of H1 associated.

H1 is also poly (ADP- ribosyl ) IERT. This change in the 60 to 80 ADP-ribose molecules are attached at several places to H1 ( for example, by the enzyme PARP -1), leads to an opening of the nucleosome and is related to DNA repair.

Other histone proteins

• H2A
• H2B
• H3
• H4