title: Ca2+-binding proteins in nuclei.
abstract: Nuclei isolated from skeletal muscle of 15-day-old chick embryos, adult chickens, rabbits and from rat liver contain on the average 8-18 nmol Ca2+/mg protein. Digestion of nuclei with DNAase I and RNAase at 37 degrees C for 8--12 h reduced the Ca2+ binding by more than 90%. After nuclease treatment, Ca2+-binding proteins were identified in the nonhistone chromosomal protein fractions and in the insoluble residue by equilibrium dialysis and centrifuge transport, in media of 0.1 M KCl and 1 mM MgCl2. The interaction of Ca2+-binding proteins with chromatin may be of importance in the regulation of the gene expression in response to changes in cytoplasmic and nucleoplasmic free-Ca2+ concentration.
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002642:Chick Embryo; D002645:Chickens; D002868:Chromosomal Proteins, Non-Histone / Q000302:isolation & purification / Q000378:metabolism*; D003850:Deoxyribonuclease I; D003851:Deoxyribonucleases / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004720:Endonucleases / Q000378:metabolism; D008099:Liver / Q000032:analysis; D009132:Muscles / Q000032:analysis; D011817:Rabbits; D051381:Rats; D012260:Ribonucleases / Q000378:metabolism; D013347:Subcellular Fractions / Q000032:analysis
chemical_list: D002135:Calcium-Binding Proteins; D002868:Chromosomal Proteins, Non-Histone; D003851:Deoxyribonucleases; D004720:Endonucleases; D012260:Ribonucleases; D003850:Deoxyribonuclease I; D002118:Calcium