Novel Smooth Muscle Cell Lines from Transgenic Mice Harboring Temperature-sensitive SV40 Large T-antigen Gene. Temperature-dependent Expression of Smooth Muscle Myosin Heavy Chain-1 and Calponin Genes

We have established novel vascular smooth muscle cell lines (SVS30 and SVS24 cells) which retain the expression of specific markers for smooth muscle cells, such as α-actin, smooth muscle myosin heavy chain-1, and calponin, from transgenic mice harboring the temperature-sensitive SV40 large T-antigen gene. SVS cell lines showed temperature-dependent growth and the expression of SV40 large T-antigen. Interestingly, protein and mRNA levels of smooth muscle myosin heavy chain-1 and calponin seen in culture at the non-permissive temperature (39°C) were higher than those at the permissive temperature (33°C). These results suggest that SV40 large T-antigen affects the expression of smooth muscle-specific markers in SVS cell lines, and that some of the characters in SVS cell lines can be controlled by culture temperature. SVS cell lines should be quite valuable tools with which to study the regulation of phenotypic modulation of smooth muscle cells, and to identify smooth muscle specific transcription factors which involve the expression of smooth muscle myosin heavy chain-1 and calponin genes.