Open AccessKinetics of Synthesis and Processing of Precursor Polypeptides of Murine Leukemia Virus in Frog Oocytes following Microinjection of Viral RNA
Author(s) -
ASSELBERGS Fred A. M.,
SALDEN Martin H. L.,
BLOEMENDAL Hans
Publication year - 1980
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1980.tb04807.x
Subject(s) - microinjection , xenopus , rna , translation (biology) , biology , murine leukemia virus , microbiology and biotechnology , cytoplasm , protein biosynthesis , virus , messenger rna , virology , biochemistry , gene
Microinjection of Rauscher murine leukemia viral RNA into living oocytes from Xenopus laevis , in contrast to cell‐free systems, allowed detailed studies on the processing of newly synthesized viral precursor polypeptides. The viral messenger appeared to be stable for at least 5 days. Maximal rate of translation of 70‐S virion RNA was observed 10 h after injection. The predominant translation products after a 1‐h labeling period were three precursor polypeptides of M r 77000, 75000 and 65000. Following longer labeling periods the most stable precursor polypeptide of M r 65000 was most prominent. In addition, several intermediates of M r 35000–60000 were observed. After about 24 h, mature viral core proteins appeared. The rate of synthesis of the 75000‐ M r and 77000‐ M r viral proteins decreased gradually after injection, suggesting that viral core polypeptides somehow regulated processing or synthesis of the group‐specific antigen precursors. A heterogeneous group of 90000–95000‐ M r polypeptides seemed to be post‐translationally modified products of the 75000‐ M r and 77000‐ M r proteins. However, in this study no envelope‐related polypeptides were synthesized, when viral RNA (70‐S or 35‐S) was injected into the cytoplasm or the nucleus of Xenopus oocytes.