Cell-free synthesized precursor to somatostatin-28 from the rat hypothalamus.
Cell-free translation of rat hypothalamic mRNA and specific immunoprecipitation were used to identify a polypeptide of 16,000 apparent molecular weight as prepro-somatostatin. Quantifying these results suggested that the somatostatin-specific mRNA represented less than 0.01% of the total hypothalamic mRNA. Co-translational addition of microsomal membranes led to the in vitro synthesis of a pro-form of 14,500 molecular weight. By using antisera specifically recognizing 3 different but overlapping segments of somatostatin-28 (SRIF-28), the rat prepro-somatostatin was shown to contain antigenic determinants of this N-terminally extended somatostatin as well as of the tetradecapeptide (SRIF-14). Sequential immunoprecipitation experiments implied the existence of only a single somatostatin precursor among the rat hypothalamic translation products, which would have to be differentially processed to allow release of both SRIF-28 and SRIF-14.
D000818:Animals; D007031:Hypothalamus / Q000032:analysis*; D008970:Molecular Weight; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000276:immunology / Q000302:isolation & purification*; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000276:immunology / Q000302:isolation & purification; D053561:Somatostatin-28
D011498:Protein Precursors; D012333:RNA, Messenger; D013004:Somatostatin; D053561:Somatostatin-28