The DEAD-box protein Dbp5p is required to dissociate Mex67p from exported mRNPs at the nuclear rim.

摘要: Eukaryotic mRNAs are exported from the nucleus to cytoplasm as complex mRNA-protein particles (mRNPs), and translocation through nuclear pore (NPC) is accompanied by extensive structural changes of mRNP. We have tested hypothesis that DEAD-box ATPase Dbp5p required for such an mRNP rearrangement. In dbp5 mutant cells, mRNA export receptor Mex67p accumulates on mRNA. This aberrant accumulation with RNA cold-sensitive growth phenotype a allele suppressed mex67 mutation. Moreover, Mex67 bound at rim in temperature-sensitive when exosome impaired. Importantly, although Mex67p-containing mRNPs also observed basket component mutated, these still contain factor Yra1p. contrast, dbp5-trapped lack propose Dbp5p's function specifically displace mRNPs, thus terminating export.