Functional characterization of IRESes by an inhibitor of the RNA helicase eIF4A.
RNA helicases are molecular motors that are involved in virtually all aspects of RNA metabolism. Eukaryotic initiation factor (eIF) 4A is the prototypical member of the DEAD-box family of RNA helicases. It is thought to use energy from ATP hydrolysis to unwind mRNA structure and, in conjunction with other translation factors, it prepares mRNA templates for ribosome recruitment during translation initiation. In screening marine extracts for new eukaryotic translation initiation inhibitors, we identified the natural product hippuristanol. We show here that this compound is a selective and potent inhibitor of eIF4A RNA-binding activity that can be used to distinguish between eIF4A-dependent and -independent modes of translation initiation in vitro and in vivo. We also show that poliovirus replication is delayed when infected cells are exposed to hippuristanol. Our study demonstrates the feasibility of selectively targeting members of the DEAD-box helicase family with small-molecule inhibitors.
Department of Biochemistry, McIntyre Medical Sciences Building Rm. 810, 3655 Promenade Sir William Osler, McGill University, Montreal, Quebec H3G 1Y6, Canada.
Marie-Eve
ME
Bordeleau
Ayaka
A
Mori
Monika
M
Oberer
Lisa
L
Lindqvist
Louisa S
LS
Chard
Tatsuo
T
Higa
Graham J
GJ
Belsham
Gerhard
G
Wagner
Junichi
J
Tanaka
Jerry
J
Pelletier
D000255:Adenosine Triphosphate / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D039601:Eukaryotic Initiation Factor-4A / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008957:Models, Genetic; D010957:Plasmids / Q000378:metabolism; D017955:Poliovirus / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014176:Protein Biosynthesis; D012313:RNA / Q000737:chemistry; D020365:RNA Helicases / Q000737:chemistry*; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D012270:Ribosomes / Q000737:chemistry*; D013329:Structure-Activity Relationship; D014162:Transfection
D003432:Cross-Linking Reagents; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012313:RNA; D000255:Adenosine Triphosphate; D039601:Eukaryotic Initiation Factor-4A; D020365:RNA Helicases