Analysis of poly(A) + RNA distribution during maize somatic embryogenesis using digoxigenated oligo-dT probes

Abstract

The pattern of total transcription activity in terms of steady state levels of poly(A)+ containing mRNA during callus initiation and somatic embryogenesis in a high (A188) and a low (A632) embryogenic line of maize was analyzed using digoxigenin labelled oligo-dT probes. A gradual increase and a preferential accumulation of label was observed in both lines, differing temporally up to 4 days in culture. In the A188 line of maize the callus gave rise to somatic embryos. The globular embryos showed less label than the callus; this labelling was mostly present in the basal part of the embryos. At a later stage upper embryogenic and lower non-embryogenic layers were observed in the A188 callus, showing conspicuous differences in the amount of label. In the late globular stage the poly(A)+ RNA signals were seen all over the embryo but at the junction of the suspensor and the callus tissue no label was observed.