Phytochrome control of gene expression in radish seedlings I. Far-red light mediated stimulation of polyribosome formation and appearance of translatable mRNAs

Abstract

Illumination of radish seedlings with far-red light brings about an increase of the polyribosome content of cotyledons and hypocotyls. Poly(A)-containing RNA from cotyledons of both etiolated and far-red light-treated radish seedlings were isolated and translated in a rabbit reticulocyte lysate. The comparison of translation products showed that the relative levels of translatable mRNA coding for six abundant polypeptides were higher in the extracts of irradiated seedlings. The comparison of mRNA populations was also investigated with respect to organ specificity, polyribosomal localization and inhibition with the cap analoge, 7-methylguanosine 5′-phosphate (pm⁷G).