Light regulates the gene expression of ribulosebisphosphate carboxylase at the levels of transcription and gene dosage in greening pea leaves

Ribulosebisphosphate carboxylase, composed of large and small subunits, is induced by light in pea leaves. During induction, the synthesis rate of the two mRNAs and the gene dosage were measured. The relative rates of synthesis of the two mRNAs changed with the time of illumination, while the relative gene dosage changed only for the large subunit. The increase in the synthesis rate of the large subunit mRNA was shown to be at least partly due to an increase in gene dosage. These results indicate that the light induction of ribulosebisphosphate carboxylase in the pea is controlled at the levels of transcription and, for the large subunit, also of gene dosage.