出版社：American Society for Biochemistry and Molecular Biology
摘要：Transcriptional profiles of Caenorhabditis elegans grown on unmethylated sterols (desMSs) or on 4α-methylsterols (4MSs) were compared using microarrays. Thirty-four genes were upregulated and 2 were downregulated >2-fold by growth on 4MSs, including 13 cuticle collagen ( col ) genes, 1 cuticulin gene ( cut-1 ), 2 groundhog-like ( grl ) genes, and 1 groundhog gene ( grd-4 ); col-36 and grl-20 were increased 12- and 19-fold, respectively. Fifteen of these 17 genes have been assigned to metabolic mountain 17, suggesting coordinate 4MS-mediated regulation of expression. Quantitative RT-PCR was performed on 27–51 h old animals grown on cholesterol (a desMS) or lophenol (a 4MS). col-36 and grl-20 showed similar cyclic peaks of expression in cholesterol and similar alterations in lophenol, suggesting coregulation. Of six additional grl genes, only grl-3 was upregulated on lophenol; the rest were downregulated. Cyclicity of expression was lost or altered in all six. Nuclear receptor genes nhr-23 , nhr-25 , nhr-41 , and daf-12 all showed cyclic expression in cholesterol and significant downregulation in lophenol by RT-PCR. Expression of the insulin-like receptor daf-2 was lower in lophenol, whereas that of its major downstream target daf-16 was higher. Thus, major changes in gene expression accompany growth on 4MSs, but with surprisingly little effect on normal growth and development.
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