Characterization of polysomes and incorporation in vitro of leucine and lysine in normal and opaque-2 zea mays endosperm during development

Abstract

Polysome preparations obtained from opaque-2 and normal maize endosperms during development did not show any significant difference in sedimentation coefficient or nucleotide composition. The pattern of incorporation in vitro of lysine and leucine, however, differed quite distinctly in these two preparations. During early stages of maturity the polysomes from opaque-2 incorporated substantially more lysine and less leucine as compared with those from normal maize. Although the trend was reversed at 25 days post-pollination, this did not result in any significant zein accumulation since very little total protein was synthesized after that stage in opaque-2 maize endosperm. It is, therefore, suggested that the opaque-2 gene exerts a regulatory control on mRNA synthesis, required for zein formation at early stages of maturation.