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：1981
卷号：78
期号：11
页码：6898-6902
DOI：10.1073/pnas.78.11.6898
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Myosin heavy chain messenger ribonucleoprotein particles (MHC mRNPs) have been isolated. Characterization of the RNA components revealed an mRNA of approximately the same size as tobacco mosaic virus RNA and three low molecular weight components. The protein consists of 9-10 major bands ranging in molecular weight between 22,000 and 130,000. The messenger contained in these mRNPs was found to direct the synthesis of both fast-muscle and slow-muscle MHC in a cell-free system. When MHC [3H]mRNPs were encapsulated into liposomes and subsequently delivered to myoblasts and myotubes, the mRNPs were taken up by the cells at both stages of differentiation. However, the MHC [3H]mRNPs taken up by the myoblasts remained as free cytoplasmic particles (80-120S), whereas in myotubes the incorporated mRNP RA was associated with polysomes. The results indicate that MHC mRNPs contain a repressor molecule(s) and that myotubes possess a mechanism for activating these mRNPs that is absent from myoblasts.
