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Induction of fibronectin expression, actin cable formation, and entry into S phase following reexpression of T antigen in mouse macrophages transformed by the tsA 640 mutant of SV40
Author(s) -
Takayama Hisao,
Tanigawa Takahiko,
Tanaka Yoshinori,
Kimura Genki
Publication year - 1986
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041280219
Subject(s) - fibronectin , cycloheximide , microbiology and biotechnology , cytoplasm , actin , biology , immunofluorescence , antigen , cell culture , protein biosynthesis , antibody , immunology , extracellular matrix , genetics
Mouse macrophages transformed by a temperature‐sensitive mutant ( tsA 640) of simian virus 40 (SV40) were examined by immunofluorescence microscopy for fibronectin expression and actin distribution. Resting cultures of tsA 640 transformants incubated at a temperature nonpermissive for SV40 large T antigen (39.0°C) exhibited phagocytic activity and did not exhibit cellular fibronectin and actin cables, like primary cultures of resident macrophages. When the resting cultures were sparsely seeded and shifted down to the permissive temperature of 33.0°C, expression of large T antigen in the nucleus, expression of fibronectin in the cytoplasm, and cellular entry into S phase occurred in that temporal order, followed by actin cable formation, cellular proliferation, and diminishment of phagocytic activity. The expression of T antigen and fibronectin was sensitive to actinomycin D and cycloheximide. The expression of fibronectin was insensitive to inhibitors of DNA synthesis, whereas the expression of actin cables was sensitive. These results suggest that SV40 T antigen leads macrophages to express fibronectin and actin cables, as well as resumption of cell proliferation, and that entry into S phase is not required for fibronectin expression but may be required for actin cable formation.