scholarly journals B-Myb acts as a repressor of human COL1A1 collagen gene expression by interacting with Sp1 and CBF factors in scleroderma fibroblasts

2004 ◽  
Vol 378 (2) ◽  
pp. 609-616 ◽  
Author(s):  
Lucia CICCHILLITTI ◽  
Sergio A. JIMENEZ ◽  
Arturo SALA ◽  
Biagio SAITTA

We investigated the role of B-Myb, a cell-cycle-regulated transcription factor, in the expression of the α1 (I) pro-collagen gene (COL1A1) in scleroderma fibroblasts. Scleroderma or SSc (systemic sclerosis) is a fibrotic disease characterized by excessive production of extracellular matrix components, especially type I collagen. Northern-blot analysis showed an inverse relationship between COL1A1 mRNA expression and that of B-Myb during exponential cell growth and during quiescence in human SSc fibroblasts. Overexpression of B-Myb in SSc fibroblasts was correlated with decreased COL1A1 mRNA expression. Transient transfections localized the down-regulatory effect of B-Myb to a region containing the proximal 174 bp of the COL1A1 promoter that does not contain B-Myb consensus binding sites. Gel-shift analysis, using nuclear extracts from normal and SSc fibroblasts transfected with B-Myb, showed no differences in DNA–protein complex formation when compared with the nuclear extracts from mock-transfected cells. However, we found that B-Myb decreases Sp1 (specificity protein 1) and CBF (CCAAT-binding factor) binding for their specific sites localized in the 174 bp COL1A1 proximal promoter. These results were also confirmed using B-Myb-immunodepleted nuclear extracts. Furthermore, immunoprecipitation assays using SSc nuclear extracts demonstrated a physical interaction of B-Myb with Sp1 and CBF transcription factors, and also an interaction between Sp1 and CBF. In addition, by employing full-length or deleted B-Myb cDNA construct, we found that B-Myb down-regulates the COL1A1 proximal promoter through its C-terminal domain. Thus these results suggest that B-Myb may be an important factor in the pathway(s) regulating collagen production in SSc fibroblasts.

1991 ◽  
Vol 278 (3) ◽  
pp. 863-869 ◽  
Author(s):  
E M L Tan ◽  
J Peltonen

Keloids are benign cutaneous tumours characterized by excess deposition of collagen, specifically type I collagen. We report here that collagen biosynthesis, as measured by hydroxyproline synthesis, was markedly inhibited by 65-80% by the combination of endothelial cell growth factor (ECGF) supplement and heparin in keloid fibroblast cultures. Fibroblast cultures that were incubated with ECGF alone also demonstrated a measurable decrease of approx. 50% in collagen synthesis compared with control cultures. The inhibition of collagen synthesis was related to the down-regulation of collagen gene expression. Quantitative measurements of mRNA-cDNA hybrids revealed that the gene expression of collagen type I was decreased by more than 80% by heparin and ECGF. Markedly diminished levels of mRNA encoding collagen type I were also observed in cultures incubated with ECGF alone. The results show that ECGF and heparin elicit a negative regulatory effect on collagen production, and that this inhibition is due largely to the down-regulation of the pro-alpha 1(I) of type I collagen gene. Furthermore, ECGF has a potent suppressive effect, and heparin provides an additive effect to this inhibitory phenomenon.


1984 ◽  
Vol 4 (9) ◽  
pp. 1843-1852
Author(s):  
R J Focht ◽  
S L Adams

We analyzed the control of type I collagen synthesis in four kinds of differentiated cells from chicken embryos which synthesize very different amounts of the protein. Tendon, skin, and smooth muscle cells were found to have identical amounts of type I collagen RNAs; however, the RNAs had inherently different translatabilities, which were observed both in vivo and in vitro. Chondrocytes also had substantial amounts of type I collagen RNAs, even though they directed no detectable synthesis of the protein either in vivo or in vitro. Type I collagen RNAs in chondrocytes display altered electrophoretic mobilities, suggesting that in these cells the reduction in translational efficiency may be mediated in part by changes in the RNA structure. These data indicate that control of type I collagen gene expression is a complex process which is exerted at both transcriptional and post-transcriptional levels.


2016 ◽  
Vol 81 (2) ◽  
pp. 376-379 ◽  
Author(s):  
Eriko Uehara ◽  
Hideki Hokazono ◽  
Takako Sasaki ◽  
Hidekatsu Yoshioka ◽  
Noritaka Matsuo

1992 ◽  
Vol 89 (5) ◽  
Author(s):  
Monica Mottes ◽  
Antonella Sangalli ◽  
Maurizia Valli ◽  
MacarenaGomez Lira ◽  
Ruggero Tenni ◽  
...  

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