期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1973
卷号：70
期号：12
页码：3641-3645
DOI：10.1073/pnas.70.12.3641
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Polydisperse high-molecular-weight RNA of nucleated avian erythrocytes includes sequences coding for globin chains. The RNA was extracted from immature erythrocytes of ducks and fractionated under denaturing conditions by sucrose density gradient centrifugation in 99% dimethylsulfoxide. The RNA sedimenting faster than 45 S was able to direct the synthesis of duck globins in the Krebs II ascites cell-free protein-synthesizing system. The newly synthesized globin molecules have been identified by their characteristic electrophoretic properties in polyacrylamide gels containing either urea or sodium dodecyl sulfate, and by immunoprecipitation of the released globin chains by rabbit antibodies against duck hemoglobin. In order to rule out the possibility of a contamination of the high-molecular-weight RNA with duck-globin messenger RNA tailing from the 9-10S region, rabbit-globin messenger RNA was added to duck RNA as an internal control. No rabbit-globin messenger RNA activity could be detected in the RNA fractions sedimenting faster than 45 S. It is concluded that high-molecular-weight RNAs in the nucleated erythroid cell contain sequences of globin messenger RNAs covalently attached to larger polynucleotide chains. These results support the view that polydisperse nuclear RNA is the precursor of the cytoplasmic messenger RNA fraction.
