[Transcription factors STAT1 and STAT3 are localized in different compartments of rat embryo fibroblasts transformed by E1A and Ha-Ras oncogenes].
Intracellular distribution of STAT1 and STAT3 transcription factors in normal fibroblasts (REF) and in E1A + Ha-Ras transformed cells has been studied by means of indirect immunofluorescence. The obtained data evidence that in REF cells, in response to the growth factor addition, STAT1 and STAT3 proteins are redistributed from the cytoplasm to the nucleus. In transformants E1A + Ha-Ras, however, significantly different pictures can be seen: while STAT1 is found to be constitutively localized in the cell nuclei, STAT3 is predominantly revealed in the cytoplasm. The data obtained from fractionation of subcellular structures confirm in general the immunofluorescence results on the cytoplasmic localization of STAT3 protein in E1A + Ha-Ras transformants. Thus, transformation of REF cells with E1A + Ha-Ras oncogenes causes a constitutive activation of STAT1 and STAT3 transcription factors, the proteins, however, being distributed in different cell compartments.
Poselova
T V
TV
Institute of Cytology, Russian Academy of Sciences, St. Petersburg.
Evdonin
A L
AL
Medvedeva
N D
ND
Pospelov
V A
VA
D017500:Adenovirus E1A Proteins / Q000235:genetics; D000818:Animals; D002451:Cell Compartmentation; D002461:Cell Line, Transformed; D004268:DNA-Binding Proteins / Q000032:analysis*; D004622:Embryo, Mammalian / Q000502:physiology; D005326:Fetal Proteins / Q000032:analysis*; D005347:Fibroblasts / Q000502:physiology; D011905:Genes, ras; D009857:Oncogenes; D051381:Rats; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D015398:Signal Transduction / Q000502:physiology*; D015534:Trans-Activators / Q000032:analysis*
D017500:Adenovirus E1A Proteins; D004268:DNA-Binding Proteins; D005326:Fetal Proteins; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; C494081:Stat1 protein, rat; C494088:Stat3 protein, rat; D015534:Trans-Activators