Cloning of double stranded DNAs derived from polysomal mRNA of maize endosperm: isolation and characterisation of zein clones.

Starting from polysomal RNA of developing maize endosperm and applying the cloning procedure of integrating dsDNA into the Pst I site of plasmid pBR 322, clones containing sequences complementary to endosperm mRNAs were obtained. 25 per cent of these clones were identified as containing zein specific DNA sequences which hybridized either with the zein mRNA coding for the 22 000 Mr protein or with the zein mRNA coding for the 19 000 Mr protein. The zein-specific DNA inserts of the recombinant plasmids were further characterized by restriction enzyme analysis.