Dynamic Interaction of Water Molecules, Inorganic Ions and Chromatin Structures in Isolated Thymus Nuclei

Abstract

In the last decade,our knowledge has tremendously improved as far as the molecular anatomy of the genes concerned,but the mechanism of the structural and functional organization of the genetic material within the nucleus of the living cell is still obscure.What we know is that the water molecules,inorganic ions and certain mobile proteins are involved in the dynamic supra-molecular organization of the genetic material (Agutter and Richardson,1980;Belmont and Nicolini,1981;Bonner,1978;Cameron et al.,1977;Kellermayer et al.,1974;Kellermayer,1987).The relationship between hydration of chromatin,volume changes of nuclei and the gene activity can be well documented with one of our earlier observations on nuclei of chicken erythrocytes hybridised with SV 40 virus induced tumor(H-50) cells (Kellermayer et al.,1978).Nuclei of the chicken erythrocytes are inactive as far as their DNA and RNA synthesis concerned,but after insertion into actively growing cells,they undergo a rapid reactivation (Harris,1967).Twenty-four hours after fusion, parallel with the activation of the gene functions,the total dry mass of the inserted nuclei increases,but the mass concentration decreases (Table l.).The increased dry mass of the active nuclei is mainly due to the intranuclear accumulation of mobile proteins,but there is no reasonable explanation why the water content of the chromatin structures are higher in the larger,active than in the smaller,inactive nuclei.