IGF-I increases c-fos expression in FRTL5 rat thyroid cells by activating the c-fos promoter
1Department of Medicine, Veterans' Administration Medical Center, San Francisco, California 94121.
Abstract:
We studied the effect of IGF-1 on c-fos mRNA expression in FRTL5 rat thyroid cells. IFG-1, or calf serum, transiently increased c-fos mRNA levels in quiescent FRTL5 cells, with the latter being more potent. This increase was prevented by actinomycin D. FRTL5 cells were stably transfected with the c-fos promoter linked upstream to the reporter gene chloramphenicol acetyl transferase (CAT). Calf serum and IGF-1 increased c-fos promoter activity in a prolonged manner, and to an equal degree. Our data indicate that IGF-1, as well as additional factor(s) in serum, increase c-fos mRNA levels, at least in part, by activation of the c-fos promoter.
Related Concept Videos
Co-activators and Co-repressors
Reporter Genes
Commonly used reporter...
General Transcription Factors
TGF - β Signaling Pathway
GPCRs Regulate Adenylyl Cylase Activity
Two...
Synthesis and Regulation of Thyroid Hormones
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...


