Transformation fingerprint: induced STAT3-C, v-Src and Ha-Ras cause small initial changes but similar established profiles in mRNA.
Induced transformation of mouse fibroblasts was carried out by releasing tetracycline-repressed expression of an oncogenic mutant of STAT3, STAT3-C, or of v-Src or Ha-Ras. At 15 days after derepression of each oncogene, DNA microarrays showed elevation (>3-fold) of a similar group of approximately 25 mRNAs compared to untransformed cells. RT-PCR confirmed a number of these mRNA elevations. RNA samples were then analysed at intervals during the first 24 h after doxycycline removal to determine the time of early changes. Extensive changes were not observed by array analysis, except in v-Src-expressing cells where about 10 mRNAs were elevated threefold or more. However, RT-PCR did uncover changes in each derepressed cell type that included some of the changes observed after the 15-day transformation period. In addition, STAT3-C target genes such as BclXI and cyclin D1, which were not observed on array analysis, were elevated by RT-PCR analysis. We conclude, therefore, that early after oncogene induction, transcriptional changes, including those initiated by STAT3-C, may occur only in scarce mRNA and/or to a limited extent. However, with additional time and probably additional cell division, a new epigenetic state is established that is mirrored by a changed transcriptional profile emblematic of transformation by each of three oncogenes.
Paz
Keren
K
Laboratory of Molecular Cell Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Socci
Nicholas D
ND
van Nimwegen
Erik
E
Viale
Agnes
A
Darnell
James E
JE
D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000502:physiology; D051379:Mice; D015688:Oncogene Protein pp60(v-src) / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; D015534:Trans-Activators; D015688:Oncogene Protein pp60(v-src); D018631:ras Proteins