The mechanisms of long-term adaptation to low oxygen environment are quite well 
studied, but little is known about the sensing of oxygen shortage, the signal 
transduction and the shortterm effects of hypoxia in plant cells. We have found 
that an RNA helicase eIF4A-III, a putative component of the Exon Junction 
Complex, rapidly changes its pattern of localisation in the plant nucleus under 
hypoxic conditions. In normal cell growth conditions GFPeIF4A-III was mainly 
nucleoplasmic, but in hypoxia stress conditions it moved to the nucleolus and 
splicing speckles. This transition occurred within 15-20 min in Arabidopsis 
culture cells and seedling root cells, but took more than 2 h in tobacco BY-2 
culture cells. Inhibition of respiration, transcription or phosphorylation in 
cells and ethanol treatment had similar effects to hypoxia. The most likely 
consequence is that a certain mRNA population will remain bound to the eIF4A-III 
and other mRNA processing proteins, rather than being transported from the 
nucleus to the cytoplasm, and thus its translation will be suspended.