Exp Mol Med.  2001 Dec;33(4):269-275.

Transcriptional repression of type I procollagen genes during adipocyte differentiation

• Yi TG
• Choi HM
• Park RW
• Sohn KY
• Kim IS

Abstract

Adipocyte differentiation is a very complex process in which whole-cell changes are accompanied. Among them, type I procollagen gene has been shown to specifically decrease during adipocyte differentiation; however, little is known about the molecular mechanism. To examine how type I procollagen gene expression is regulated at the level of transcription during adipocyte differentiation, 3T3-L1 preadipocyte cell line was used as an in vitro model. Northern blot analysis demonstrated that mRNA expression of type I procollagen gene was dramatically reduced during adipocyte differentiation. Time-course analysis indicated that decrease in mRNA expression occurred at early stage of differentiation. Studies on several stable cell lines showed that transcriptional activities of both alpha1 and alpha2 promoters decreased significantly during adipocyte differentiation. Despite extensive deletion-promoter analyses, however, we could not identify the cis-element responsible for the switch-off of type I procollagen gene during adipocyte differentiation, suggesting that the transcriptional repression of this gene occur through general transcription machinery rather than a specific cis-element. In conclusion, down-regulation of type I procollagen mRNA expression during adipocyte differentiation is due to repression of its promoter activity through general transcription machinery.

Keyword

Procollagen; adipocyte differentiation; transcription; repression

MeSH Terms

3T3 Cells
Adipocytes/cytology/*metabolism
Animal
Cell Differentiation/*genetics
Cell Line
Collagen Type I/*genetics/metabolism
Down-Regulation/genetics
Gene Expression Regulation
Genes, Reporter
Kinetics
Mice
Mutation
Procollagen/*genetics/metabolism
Promoter Regions (Genetics)
RNA, Messenger/metabolism
Repressor Proteins/genetics/metabolism
Transcription, Genetic