What are histones? What are their functions?

Histones are basic proteins, which are soluble in water or dilute acids but are insoluble in dilute ammonia . They are rich in basic amino acids like histidine and arginine. Histones are readily hydrolysed by trypsin and pepsin and are considered as gene repressors. The histone proteins are not coagulated by heat and are also found to he associated with DNA of nucleus forming the chromatin material.