Background and Objectives : As a part of efforts to evaluate effectiveness of aorta
cell lineages derived from the transgenic mice in which expression of the
temperature-sensitive SV40 large T antigen has been targeted to vascular smooth
muscle, localization of the T antigen gene in chromosome of the established cell lineages
was characterized. Expression pattern of p53 in an aorta cell line or those of γ-actin
and the T antigen in the various tissues of the transgenic mice, respectively, were also
examined.
Materials and Methods : Chromosomal DNA obtained from the aorta cell lines, which
were derived from the transgenic mice, was analyzed by genomic Southern blot method
to identify the transgene in genome. mRNA was prepared from the various tissues of
the transgenic mouse and was examined by Northern blot analysis to detect expression
of γ-actin gene. Reverse transcription polymerase chain reaction (RT-PCR) was also
performed to examine transcription pattern of p53 gene in an aorta cell line.
Immunohistology for detecting the T antigen expression in the tissues of the transgenic
mouse was also carried out.
Results : Correct integration of the SV40 T antigen transgene in chromosome was
observed in two aorta cell lines, although their copy numbers inserted were different
from each other. Alternative splicing of the primary p53 RNA was identified in the aorta
cells when cultured at the restrictive temperature, but not in the cells at permissive
temperature. Several tissues of the transgenic mouse showed expression of the viral
oncoprotein T antigen.
Conclusion : An established aorta cell line may be useful model to study the mechanism
regulating the proliferation of vascular smooth cells in mice. Mutant form(s) of the p53
tumor suppressor protein generated by the translation of the alternatively spliced mRNA
might be involved in the blockade of apoptosis in some aorta cells when cultured at the
restrictive temperature. However, expression of the viral gene in the tissues of the
transgenic mice seemed not to be precisely regulated by temperature-dependent manner.
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