HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Stephens, J. M. Articles by Pekala, P. H. Search for Related Content PubMed PubMed Citation Articles by Stephens, J. M. Articles by Pekala, P. H.

3T3-L1 preadipocytes differentiate into cells having the biochemical properties of adipocytes; tumour necrosis factor- (TNF) attenuates this process. Inhibition of differentiation by this cytokine, thought to be mediated at the level of transcription, has been investigated by examining the accumulation of mRNA for six transcription factors and three diversely regulated genes during the first 24 h of the differentiation process. Upon induction of differentiation, a rapid and major accumulation of c-fos and jun-B mRNA, which returned to near basal levels within 4–6 h, was observed. In contrast, c-jun mRNA, although rapidly expressed at the induction of differentiation, remained at relatively constant levels throughout the time-course. Exposure of the cells to 5 nM TNF potentiated the accumulation of all three mRNAs but most significantly that of c-jun (12-fold), which remained elevated for at least 24 h after treatment. In control differentiating cells, krox-20 and fos-B were expressed transiently from 30 min to 2 h, while fra-1 mRNA accumulated over an extended period of 1 to 8 h. Again, TNF enhanced the accumulation of these mRNAs. Accumulation of mRNA for C/EBP, a transcription factor proposed to control the expression of genes involved in the terminally differentiated state, was attenuated after exposure of the cells to TNF. Interleukin-6 (IL-6) mRNA was expressed briefly (30 min to 2 h) and again transiently (at 8 h after induction of differentiation). TNF treatment markedly enhanced accumulation of IL-6 message. We propose that an increased cellular content of one or more transcription factors or the suppression of C/EBP may be responsible for the attenuation of differentiation induced by exposure of the cells to TNF.