Novel cis-active structures in the coding region mediate CRM1-dependent nuclear export of IFN-alpha 1 mRNA

作者：Kimura Tominori^*; Hashimoto Iwao; Nishizawa Mikio; Ito Seiji; Yamada Hisao

来源：Medical Molecular Morphology, 2010, 43(3): 145-157.

DOI：10.1007/s00795-010-0492-5

• Nuclear export
• IFN-alpha 1 mRNA
• RNA secondary structure
• CRM1
• RNA-fluorescence in situ hybridization
• Yeast three-hybrid assay
• RNPS1

We recently reported the chromosome region maintenance 1 (CRM1)-dependent nuclear export of intron-less human interferon-alpha 1 (IFN-alpha 1) mRNA, which encodes a main effecter of host innate immunity. We show that the coding region of IFN-alpha 1 mRNA forms novel secondary structures that are responsible for the CRM1-dependent export of the transcript. Deletion-mutagenesis, in vivo export assays, and computer analyses of the folding potentials of export-competent fragments revealed the presence of a domain, termed the conserved secondary structure (CSS), comprising two adjacent putative stable stem-loop structures (nt 208-452). Internal deletion-mutagenesis and constitutive export assays of each stem-loop structure demonstrated that subregions 308-322 and 352-434 act as a core element by conferring the export function on the CSS. Leptomycin B (LMB) inhibition of the CRM1 pathway decreased the export of core element RNA, implying that the principal site of CRM1 action for exporting IFN-alpha 1 mRNA resides within the core element. An RNPS1 (RNA-binding protein S1, serine-rich domain) cDNA was isolated by yeast three-hybrid screening, using bait containing two CSS regions. We showed that RNPS1 might recognize IFN-alpha 1 mRNP that includes CRM1. The data demonstrate that interaction between RNA structures in the coding region and CRM1 affects the nucleocytoplasmic translocation of IFN-alpha 1 mRNA.

• 出版日期2010-9