Aging Cell · 2011 · 82 citations · 17 references
Life SciencesBiochemistryMolecular BiologyMetabolic RegulationMetabolismSteroid BiochemistryCholesterol BiosynthesisCholesterol MetabolismLipid MetabolismSteroid BiosynthesisSteroidogenic EnzymesSterol Metabolism7-Dehydrocholesterol MetabolismBile Acid Regulation Of Cholesterol MetabolismC. Elegans Developmental ModelsDevelopmental Timing ControlMammalian Reproductive DevelopmentSteroidogenic Enzyme FunctionSteroidogenic Enzyme GenesSteroidogenic Regulation
Bile acids are cholesterol-derived signaling molecules that regulate mammalian metabolism through sterol-sensing nuclear receptor transcription factors. In C. elegans, bile acid-like steroids called dafachronic acids (DAs) control developmental timing and longevity by activating the nuclear receptor DAF-12. However, little is known about the biosynthesis of these molecules. Here, we show that the DAF-36/Rieske oxygenase works at the first committed step, converting cholesterol to 7-dehydrocholesterol. Its elucidation as a cholesterol 7-desaturase provides crucial biochemical evidence that such oxygenases are key steroidogenic enzymes. By controlling DA production, DAF-36 regulates DAF-12 activities for reproductive development and longevity and may illuminate related pathways in metazoans.
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Real-time quantification of microRNAs by stem-loop RT-PCR
C. Chen · Nucleic Acids Research · 2005 · 5K citations · Full text