RESUMO
[This corrects the article DOI: 10.1371/journal.pone.0197165.].
RESUMO
DBP5, also known as DDX19, GLE1 and inositol hexakisphosphate (IP6) function in messenger RNA (mRNA) export at the cytoplasmic surface of the nuclear pore complex in eukaryotic cells. DBP5 is a DEAD-box RNA helicase, and its activity is stimulated by interactions with GLE1 and IP6. In addition, these three factors also have unique role(s). To investigate how these factors influenced the cytoplasmic mRNA expression and cell phenotype change, we performed RNA microarray analysis to detect the effect and function of DBP5, GLE1 and IP6 on the cytoplasmic mRNA expression. The expression of some cytoplasmic mRNA subsets (e.g. cell cycle, DNA replication) was commonly suppressed by the knock-down of DBP5, GLE1 and IPPK (IP6 synthetic enzyme). The GLE1 knock-down selectively reduced the cytoplasmic mRNA expression required for mitotic progression, results in an abnormal spindle phenotype and caused the delay of mitotic process. Meanwhile, G1/S cell cycle arrest was observed in DBP5 and IPPK knock-down cells. Several factors that function in immune response were also down-regulated in DBP5 or IPPK knock-down cells. Thereby, IFNß-1 mRNA transcription evoked by poly(I:C) treatment was suppressed. These results imply that DBP5, GLE1 and IP6 have a conserved and individual function in the cytoplasmic mRNA expression. Variations in phenotype are due to the difference in each function of DBP5, GLE1 and IPPK in intracellular mRNA metabolism.
Assuntos
RNA Helicases DEAD-box/metabolismo , Fase G1 , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Ácido Fítico/metabolismo , RNA Mensageiro/metabolismo , Fase S , Transporte Biológico Ativo/genética , Citoplasma/genética , Citoplasma/metabolismo , RNA Helicases DEAD-box/genética , Células HeLa , Humanos , Interferon beta/genética , Interferon beta/metabolismo , Proteínas de Transporte Nucleocitoplasmático/genética , Fosfotransferases (Aceptor do Grupo Álcool)/genética , RNA Mensageiro/genéticaRESUMO
In eukaryotic cells, RNAs are transcribed in the nucleus and exported to the cytoplasm through the nuclear pore complex. The RNA molecules that are exported from the nucleus into the cytoplasm include messenger RNAs (mRNAs), ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), small nuclear RNAs (snRNAs), micro RNAs (miRNAs), and viral mRNAs. Each RNA is transported by a specific nuclear export receptor. It is believed that most of the mRNAs are exported by Nxf1 (Mex67 in yeast), whereas rRNAs, snRNAs, and a certain subset of mRNAs are exported in a Crm1/Xpo1-dependent manner. tRNAs and miRNAs are exported by Xpot and Xpo5. However, multiple export receptors are involved in the export of some RNAs, such as 60S ribosomal subunit. In addition to these export receptors, some adapter proteins are required to export RNAs. The RNA export system of eukaryotic cells is also used by several types of RNA virus that depend on the machineries of the host cell in the nucleus for replication of their genome, therefore this review describes the RNA export system of two representative viruses. We also discuss the NPC anchoring-dependent mRNA export factors that directly recruit specific genes to the NPC.
RESUMO
A number of proteins complete mRNA processing in the nucleus, thus, inhibitor of mRNA processing is worth finding to analyze the mechanism of mRNA maturation in detail. Here, we established a monitoring system for mRNA processing using a test compound, spliceostatin A (SSA), which inhibits mRNA splicing. This system should serve to facilitate the discovery of novel compounds from natural resources that inhibit mRNA processing.