The influence of poly(A)-binding proteins on translation of poly(A) + RNA in a cell-free system from embryo axes of dry pea seeds

Abstract

Ribonucleoproteins of the ribosomal fraction of germinated pea embryo axes, containing translationally active mRNA, differ from analogous ribonucleoproteins of dry pea seeds, which contain stored mRNA, by the presence of a 60 kDa protein fraction showing affinity to poly(A). The above protein fraction largely affects the activity of poly(A) + RNA translation in cell-free system. An activating effect is clearly seen at a weight ratio of poly(A)-binding proteins:poly(A) + RNA of 3:1, whereas with an increase in the concentration of these proteins the translational activity drops. The effect of poly(A)-binding proteins containing the 60 kDa fraction on poly(A) + RNA dependent cell-free translation can be efficiently reduced by simultaneous addition of synthetic poly(adenylic acid). It was also proved that activation of translation does not influence its products. It is concluded that poly(A)-binding proteins from the ribosomal fraction of embryo axes of pea seeds, especially the 60 kDa fraction, are involved in regulation of the translational activity of poly(A) + RNA.