Cytokinin modulation of LHCP mRNA levels: the involvement of post-transcriptional regulation

✍ Scribed by Susan Flores; Elaine M. Tobin

• Publisher: Springer
• Year: 1988
• Tongue: English
• Weight: 639 KB
• Volume: 11
• Category: Article
• ISSN: 0167-4412
• DOI: 10.1007/bf00039021

✦ Synopsis

When white-light-grown Lemna gibba plants are placed in the dark, the levels of mRNAs for two nuclearencoded chloroplast proteins, the small subunit of ribulose-l,5-bisphosphate carboxylase (SSU) and the major chlorophyll a/b-binding protein of light-harvesting complex II (LHCP), decline to a small fraction of their previous level. We have reported [4] that red light (R), acting through phytochrome, and benzyladenine (BA), a synthetic cytokinin, independently stimulate accumulation of both mRNAs in the dark. Here, we have analyzed the products of transcription in isolated nuclei to determine if cytokinins act primarily through stimulation of transcription or if post-transcriptional processes are involved. We find that BA pretreatment may slightly stimulate transcription of L H C P RNA either with or without a red-light treatment. However, the effects of BA on the L H C P RNA accumulation were much greater than on transcription. Two naturally occurring cytokinins are also effective in increasing the mRNA abundance. We therefore conclude that, in Lemna, posttranscriptional processes are important in regulation of the L H C P RNA by cytokinins.