A temperature-conditional mutant of simian virus 40 large T antigen requires serum to inhibit myogenesis and does not induce DNA synthesis in myotubes

Giovanni Salvatori, Laura Lattanzi, Pier Lorenzo Puri, Roberta Melchionna, Carlo Fieri, Massimo Levrero, Mario Molinaro, Giulio Cossu

Research output: Contribution to journalArticlepeer-review

Abstract

The temperature-conditional mutant tsA58 of SV40 large T antigen (Tag) increases the proliferation rate and the number of cell divisions in primary murine and human myogenic cells when expressed under permissive conditions (i.e., at 33°C in medium containing high levels of serum). Under these conditions, Tag also prevents terminal differentiation. Under nonpermissive conditions (i.e., at 39°C in medium containing low levels of serum) in which Tag is largely inactive, proliferation is arrested, and differentiation occurs. However, even at a permissive temperature, the removal of serum induced myosin expression and the fusion of myogenic cells, which continued to express functional Tag. Although Tag was complexed with pRb, as expected from a functional protein, proliferation was nevertheless arrested, and differentiation was induced. Consistent with these findings, the exposure of Tag-expressing differentiated myotubes to serum at 33°C did not reinduce DNA synthesis in these cells. Thus, in myogenic cells, temperature-conditional mutants of Tag stimulate proliferation in the presence of serum but neither prevent terminal differentiation in the absence of serum nor induce DNA synthesis once complete withdrawal from the cycle has occurred.

Original languageEnglish
Pages (from-to)157-164
Number of pages8
JournalCell Growth and Differentiation
Volume8
Issue number2
Publication statusPublished - 1997

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology

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