Open AccessCytoplasmic utilization of liposome-encapsulated myosin heavy chain messenger ribonucleoprotein particles. During muscle cell differentiation.
Author(s) -
Amalia S. Havaranis,
Stuart M. Heywood
Publication year - 1981
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.78.11.6898
Subject(s) - myogenesis , ribonucleoprotein , myosin , messenger rnp , microbiology and biotechnology , cytoplasm , messenger rna , myocyte , biology , polysome , major histocompatibility complex , rna , chemistry , biochemistry , ribosome , gene
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.