Multiple plastid signals regulate the expression of the pea plastocyanin gene in pea and transgenic tobacco plants.
The expression of nuclear genes encoding photosynthesis-related proteins is regulated by signals from plastids. To investigate how the pea PetE gene encoding plastocyanin is regulated by plastid signals, the effects of norflurazon, lincomycin and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), specific inhibitors of plastid-located processes generating plastid signals, have been examined. RNA-gel blot analysis of 7-day-old pea and tobacco seedlings containing the pea PetE gene showed that treatment with norflurazon and lincomycin, but not DCMU, decreased the accumulation of transcripts of pea PetE and endogenous Lhcb1 genes. Analysis of chimeric PetE gene constructs in tobacco seedlings showed that an intact PetE mRNA 5' terminus and elements within the PetE coding region were required to confer sensitivity to norflurazon and lincomycin, suggesting post-transcriptional regulation. Analysis of 4-week-old tobacco plants containing chimeric PetE constructs showed that DCMU treatment decreased the accumulation of pea PetE and Lhcb1 transcripts, but had opposite effects on the transcription of the genes in nuclear run-on assays. DCMU upregulated transcription from the pea PetE promoter whereas transcription of tobacco Lhcb1 genes was decreased. These experiments provide evidence for multiple plastid signals operating at different developmental stages and affecting transcriptional and post-transcriptional processes regulating expression of the pea PetE gene.
Sullivan
James A
JA
Department of Plant Sciences and Cambridge Centre for Molecular Recognition, University of Cambridge, Downing Street, UK.
Gray
John C
JC
D004237:Diuron / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D008034:Lincomycin / Q000494:pharmacology; D018532:Pisum sativum / Q000166:cytology / Q000187:drug effects / Q000235:genetics*; D030821:Plants, Genetically Modified; D018087:Plastids / Q000187:drug effects / Q000378:metabolism*; D010970:Plastocyanin / Q000235:genetics*; D011724:Pyridazines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014026:Nicotiana / Q000166:cytology / Q000187:drug effects / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects; D019076:Transgenes / Q000235:genetics
D011724:Pyridazines; D012333:RNA, Messenger; D018749:RNA, Plant; D010970:Plastocyanin; D004237:Diuron; D008034:Lincomycin; C008677:norflurazone