2840
Sterol regulatory element ( SRE ) has been recognized to regulate various key genes coding for especially low density lipoprotein ( LDL )-receptor , 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and HMG-CoA synthase known to play a crucial role in the cholesterol feedback mechanism .
 ( protein: low density lipoprotein, None) , ( protein: 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, None) , ( DNA: genes, None) , ( DNA: Sterol regulatory element, None) , ( protein: HMG-CoA synthase, None) , ( protein: low density lipoprotein ( LDL )-receptor, None) , ( protein: LDL, None) , ( DNA: SRE, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: low density lipoprotein, None) , ( protein: 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, None) , ( DNA: genes, None) , ( DNA: Sterol regulatory element, None) , ( protein: HMG-CoA synthase, None) , ( protein: low density lipoprotein ( LDL )-receptor, None) , ( protein: LDL, None) , ( DNA: SRE, None) 