Single gene for the large subunit of ribulosebisphosphate carboxylase in maize yields two differentially regulated mRNAs.

A second mRNA coding for the large subunit of ribulose-1,5-bisphosphate carboxylase [3-phospho-D-glycerate carboxylase (dimerizing), EC 4.1.1.39] has been found in the plastids of maize leaves. The 5' terminus of this mRNA was shown by S1 nuclease analysis to be 238 nucleotides upstream of the previously described large subunit mRNA [McIntosh, L., Poulsen, C. & Bogorad, L. (1980) Nature (London) 288, 556-560]. The same two mRNAs were produced in a homologous in vitro transcription system using cloned plastid DNA as a template. The ratio of the two mRNAs changes during light-induced plastid development and can be altered in the in vitro system by manipulation of transcription conditions.