[PDF][PDF] An SREBP-responsive microRNA operon contributes to a regulatory loop for intracellular lipid homeostasis

TI Jeon, RM Esquejo, M Roqueta-Rivera, PE Phelan… - Cell metabolism, 2013 - cell.com
TI Jeon, RM Esquejo, M Roqueta-Rivera, PE Phelan, YA Moon, SS Govindarajan, CC Esau…
Cell metabolism, 2013cell.com
Sterol regulatory element-binding proteins (SREBPs) have evolved as a focal point for
linking lipid synthesis with other pathways that regulate cell growth and survival. Here, we
have uncovered a polycistrionic microRNA (miRNA) locus that is activated directly by
SREBP-2. Two of the encoded miRNAs, miR-182 and miR-96, negatively regulate the
expression of Fbxw7 and Insig-2, respectively, and both are known to negatively affect
nuclear SREBP accumulation. Direct manipulation of this miRNA pathway alters nuclear …
Summary
Sterol regulatory element-binding proteins (SREBPs) have evolved as a focal point for linking lipid synthesis with other pathways that regulate cell growth and survival. Here, we have uncovered a polycistrionic microRNA (miRNA) locus that is activated directly by SREBP-2. Two of the encoded miRNAs, miR-182 and miR-96, negatively regulate the expression of Fbxw7 and Insig-2, respectively, and both are known to negatively affect nuclear SREBP accumulation. Direct manipulation of this miRNA pathway alters nuclear SREBP levels and endogenous lipid synthesis. Thus, we have uncovered a mechanism for the regulation of intracellular lipid metabolism mediated by the concerted action of a pair of miRNAs that are expressed from the same SREBP-2-regulated miRNA locus, and each targets a different protein of the multistep pathway that regulates SREBP function. These studies reveal an miRNA "operon" analogous to the classic model for genetic control in bacterial regulatory systems.
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