Purification and translation of zein messenger RNA from maize endosperm protein bodies

Abstract

The mRNA coding for the zein [Zea mays] storage protein were purified from other contaminating RNA. The average molecular lengths are 1.1-1.2 kilobases, as determined by polyacrylamide gel electrophoresis and by EM. Products of messenger-dependent protein synthesis in vitro appear to be 1100 and 2000 daltons heavier than the native polypeptides. Zein is like secretory proteins in having a precursor with an additional amino-terminal sequence. Although only 1 mRNA is seen in polyacrylamide gel electrophoresis, the combined size of the polypeptide products formed exceeds the coding capacity for 1 message of the size determined in this study. This suggests that there are at least 2 mRNA of similar sizes for the zein polypeptides rather than 1 dicistronic message.