Nuclear-Cytoplasmic Partitioning of Phytochrome-Regulated Transcripts in Pisum sativum.

Nuclear and cytoplasmic mRNAs for several phytochrome-regulated genes were examined in Pisum seedlings in order to investigate possible light effects on mRNA partitioning between the nucleus and cytoplasm. Transcripts from each of five light-regulated genes exhibited different responses to a variety of light treatments, but for each transcript we observed a characteristic linear relationship between nuclear and cytoplasmic levels over a wide range of total transcript abundance. Different mRNAs are characterized by different nuclear-cytoplasmic ;partitioning coefficients', indicating that post-transcriptional events play a significant role in regulating the accumulation of these mRNAs during light induction.