Thyroglobulin messenger RNA: translation of a 33-S mRNA into a peptide immunologically related to thyroglobulin.
Poly(UC)--Sepharose chromatography of the RNA extracted from a thyroid fraction sedimenting between 800 X g and 27000 X g allows the purification of two RNA fractions amounting each to 1% of the applied material. The first one is loosely bound to the column from which it is eluted at 25 degrees C. It is mainly composed of 16-S and 12-S RNA comprising no poly(A) sequences. This could correspond to mitochondrial rRNA. The second one, which is eluted at 50 degrees C, is poly(A)-rich and represents 33-S and 17--18-S RNA species. The 33-S RNA resists heating at 80 degrees C, suggesting that it is composed of one polynucleotide chain. When injected into Xenopus oocytes, the 33-S RNA specifically promotes the synthesis of a peptide with an apparent molecular weight of 185000 and an apparent sedimentation coefficient of 10-S. This peptide is immunologically related to thyroglobulin and could represent its main precursor. Under the conditions tested it does not polymerize spontaneously into 19-S thyroglobulin, suggesting that assembly of the molecule could require specific, post-translational alterations of the precursor and/or the presence of additional lighter subunits.
D000818:Animals; D002417:Cattle; D002846:Chromatography, Affinity; D005260:Female; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D009865:Oocytes / Q000378:metabolism; D010452:Peptide Biosynthesis; D010455:Peptides / Q000276:immunology; D011061:Poly A / Q000032:analysis; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism*; D013954:Thyroglobulin / Q000096:biosynthesis* / Q000276:immunology; D014981:Xenopus
D010455:Peptides; D012333:RNA, Messenger; D011061:Poly A; D013954:Thyroglobulin