Production and properties of vitamin-D-induced mRNA for chick calcium-binding protein.
1. Calcium-binding protein synthesis on chick intestinal polysomes is induced within 2 h of injecting vitamin-D-deficient birds with 1,25-dihydroxycholecalciferol. The induction is short-lived: the maximum output of the binding protein is reached by 13 h after hormone injection, and declines rapidly thereafter. 2. This induction of calcium-binding protein synthesis occurs by the production of active mRNA for the protein. The sedimentation coefficient of this mRNA in denaturing conditions is 18 S, equivalent to a molecular weight of approximately 700000, and the molecule contains a tract of polyadenylate. 3. Both polysomal and poly(A)-containing RNA extracted from intestinal polysomes stimulate the synthesis of a range of proteins (up to 70000 molecular weight) by the wheat germ cell-free system. Immunoprecipitable calcium-binding protein is translated from RNA obtained from 1,25-dihydroxycholecalciferol-dosed birds but not from control birds. This calcium-binding protein is the same size (27000 molecular weight) as authentic chick calcium-binding protein; No other proteins are specifically precipitated by the antiserum. Thus in chickens 1,25-dihydroxycholecalciferol-induced calcium-binding protein is not synthesised via any precursor molecule. The implications of this result are discussed.
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002352:Carrier Proteins / Q000032:analysis / Q000096:biosynthesis*; D002645:Chickens; D004790:Enzyme Induction; D007082:Ileum / Q000201:enzymology; D008970:Molecular Weight; D011132:Polyribosomes / Q000187:drug effects / Q000201:enzymology; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis*; D014807:Vitamin D / Q000494:pharmacology*
D002352:Carrier Proteins; D012333:RNA, Messenger; D014807:Vitamin D; D002118:Calcium