| Autor: |
Vik, D. P. |
| Předmět: |
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| Zdroj: |
Scandinavian Journal of Immunology; Sep1996, Vol. 44 Issue 3, p215-222, 8p, 1 Diagram, 1 Chart, 5 Graphs |
| Abstrakt: |
Factor H is a regulatory protein of the alternative pathway of complement activation that is synthesized mainly in the liver. The authors used the +/+ Li murine liver cell line as a model for examining its regulation. When +/+ Li cells were incubated with IFN-γ, the levels of factor H mRNA increased in a dose-dependent manner, achieving a maximal response at a concentration of 50-100 units/ml. The increase in factor H mRNA levels was paralleled by an increase in factor H secretion. The kinetics of induction of factor H mRNA were slow, with the response reaching near maximal levels at 24 h. The increase in factor H mRNA by IFN-γ was dependent on protein synthesis, as cycloheximide abolished the response. The presence of IFN-γ was required for the entire incubation period in order to produce a maximal response. The luciferase system was used in an attempt to identify an interferon-responsive element. Luciferase constructs containing from 807 to 236 bp of upstream sequence responded to IFN-γ with a twofold induction of luciferase activity, whereas a construct containing 83 bp of 5′ sequence did not. Thus, IFN-γ stimulates factor H mRNA transcription through a protein intermediary that interacts with the promoter between positions -83 and -236. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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