The s-Myc protein having the ability to induce apoptosis is selectively expressed in rat embryo chondrocytes.
Gene transfection experiments demonstrated that over-expression of the s-myc gene under the control of a human metallothionein promoter induced apoptosis in cells such as rat and human glioma cells. In contrast to c-Myc-mediated apoptosis requiring withdrawal of serum growth factors, s-myc expression induced apoptosis in glioma cells in the presence of 10% fetal calf serum. Whereas, s-Myc-mediated apoptosis was suppressed in proportion to the increase of bcl-2 expression as seen in c-Myc mediated apoptosis. The s-myc gene was expressed in rat embryo cells being committed to differentiate to hypertrophic chondrocytes which undergo programmed cell death. CAT assay demonstrated that in the NH2-terminal region, the s-Myc protein contains a domain structure required for expression of transactivation activity that is approximately six times higher than that of c-Myc. Therefore, these findings strongly suggest that s-Myc may play an important role in transcription regulation of a set of genes whose expression induces programmed cell death in vitro and in vivo.
Biophysics Division, National Cancer Center Research Institute, Tokyo, Japan.
A
A
Asai
Y
Y
Miyagi
A
A
Sugiyama
Y
Y
Nagashima
H
H
Kanemitsu
M
M
Obinata
K
K
Mishima
Y
Y
Kuchino
D016475:3T3 Cells; D000818:Animals; D017209:Apoptosis; D002356:Cartilage / Q000166:cytology* / Q000196:embryology / Q000378:metabolism; D005786:Gene Expression Regulation; D016259:Genes, myc; D005910:Glioma / Q000473:pathology; D006801:Humans; D051379:Mice; D015513:Oncogene Proteins / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2; D051381:Rats; D014157:Transcription Factors / Q000502:physiology; D014407:Tumor Cells, Cultured
D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D014157:Transcription Factors