HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Radaelli, A. Articles by De Giuli Morghen, C. Search for Related Content PubMed PubMed Citation Articles by Radaelli, A. Articles by De Giuli Morghen, C. Agricola Articles by Radaelli, A. Articles by De Giuli Morghen, C.

Ultrastructural and Biochemical Evidence that the L929 Cell Retrovirus Lacks the env Gene Translation Product

Centro del CNR per lo Studio della Farmacologia delle Infrastrutture Cellulari, via Vanvitelli, 32, 20129 Milano, Italy

LCV, a murine retrovirus released by L929 mouse cell fibroblasts, is non-infectious when inoculated into SC-1, mink, D-17 or Vero cells. Ultrastructural examination by thin sectioning, freeze-etching or negative staining revealed the absence, on the viral envelope, of the radially disposed spikes. Polyacrylamide gel electrophoresis of radiolabelled viral components showed the absence of the glycosylated protein gp70 as well as of the p15E cleavage product of the polyprotein precursor gPr90^env. The premature loss of the gp70 molecule from LCV to the culture medium was ruled out since no peak of D-[¹⁴C]glucosamine-labelled glycoprotein was detected by affinity chromatography or immunoprecipitation of concentrated medium. The ultrastructural and biochemical results all supported the hypothesis that the absence of infectivity was due to the lack of gp70 glycoprotein in the envelope of LCV. A possible block at a translational or post-translational level was also investigated by immunofluorescence studies with antisera directed against ecotropic or xenotropic gp70; Moloney murine leukaemia virus-infected or NZB cells were used as positive controls for eco- or xenotropic viruses respectively. The absence of fluorescent stain in L929 cells further supported these results and suggested that LCV and the L929 parental cell line lack the uncleaved precursor and the final product of the env gene translation process.

Keywords: L929 retrovirus, EM, gp70, infectivity

Received 20 June 1983; accepted 29 September 1983.