Abstract
DHX-9, a member of the DEXH family of RNA helicases, unwinds dsRNA/dsDNA by ATP or GTP-dependent hydrolysis. We asked whether DHX-9 played a role in the GTP depletion-induced inhibition of rRNA synthesis and/or nucleolar disruption. MPA, a specific inhibitor of inosine monophosphate dehydrogenase (IMPDH), induced a rapid translocation of DHX-9 from the nucleolus to the nucleus. EGFP-tagged DHX-9 mutated at the GTP binding site also localized to the nucleus. However, knockdown of DHX-9 by siRNA did not inhibit the rRNA synthesis or cause the nucleolar disruption. Thus, DHX-9 translocation found with IMPDH inhibition does not mediate the inhibition of rRNA synthesis.
MeSH terms
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Adenosine Triphosphate / metabolism
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Base Sequence
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Binding Sites
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Cell Line, Tumor
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DEAD-box RNA Helicases / genetics*
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DEAD-box RNA Helicases / metabolism*
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Dactinomycin / metabolism
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Gene Deletion
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Guanosine Triphosphate / metabolism*
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Humans
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IMP Dehydrogenase / antagonists & inhibitors
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IMP Dehydrogenase / metabolism
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Mutation
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Neoplasm Proteins / genetics*
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Neoplasm Proteins / metabolism*
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Nuclear Proteins / metabolism*
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Protein Transport
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RNA, Ribosomal / biosynthesis
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RNA, Small Interfering / genetics
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
Substances
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Neoplasm Proteins
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Nuclear Proteins
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RNA, Ribosomal
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RNA, Small Interfering
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Recombinant Proteins
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Dactinomycin
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Guanosine Triphosphate
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Adenosine Triphosphate
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IMP Dehydrogenase
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DHX9 protein, human
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DEAD-box RNA Helicases