TY - JOUR
T1 - Organ-specific transcription of the rrn operon in spinach plastids
AU - Iratni, Rabah
AU - Diederich, Ludger
AU - Harrak, Hassan
AU - Bligny, Muriel
AU - Lerbs-Mache, Silva
PY - 1997/5/23
Y1 - 1997/5/23
N2 - The spinach rrn operon is used as a model system to study transcriptional regulation in higher plant photosynthetic and non- photosynthetic plastids. We performed capping experiments to determine whether P1, PC, or P2 promoters are employed for rrn transcription start sites in cotyledon and root tissues. By using a new method of analysis of capped RNA we demonstrate for the first time that 1) in both organs the rrn operon is expressed in a constitutive manner by cotranscription with the preceding tRNA(GAC)(Val) gene, and 2) the PC transcription start site is used only in cotyledons and leaves, i.e. we demonstrate the organ-specific usage of a plastid promoter. Both start sites, PC and that of the tRNA(GAC)(Val) cotranscript, lack Escherichia coli-like consensus sequences. The cotranscript is initiated 457 base pairs upstream of the tRNA(GAC)(Val) gene. The PC-specific DNA-binding factor, CDF2, is not detectable in root tissues confirming its regulatory role in PC-initiated rrn expression and the organ specificity of PC expression. Furthermore, our results show that rrn operon expression patterns differ in spinach and tobacco indicating species-specific transcriptional regulation of plant plastid gene expression.
AB - The spinach rrn operon is used as a model system to study transcriptional regulation in higher plant photosynthetic and non- photosynthetic plastids. We performed capping experiments to determine whether P1, PC, or P2 promoters are employed for rrn transcription start sites in cotyledon and root tissues. By using a new method of analysis of capped RNA we demonstrate for the first time that 1) in both organs the rrn operon is expressed in a constitutive manner by cotranscription with the preceding tRNA(GAC)(Val) gene, and 2) the PC transcription start site is used only in cotyledons and leaves, i.e. we demonstrate the organ-specific usage of a plastid promoter. Both start sites, PC and that of the tRNA(GAC)(Val) cotranscript, lack Escherichia coli-like consensus sequences. The cotranscript is initiated 457 base pairs upstream of the tRNA(GAC)(Val) gene. The PC-specific DNA-binding factor, CDF2, is not detectable in root tissues confirming its regulatory role in PC-initiated rrn expression and the organ specificity of PC expression. Furthermore, our results show that rrn operon expression patterns differ in spinach and tobacco indicating species-specific transcriptional regulation of plant plastid gene expression.
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U2 - 10.1074/jbc.272.21.13676
DO - 10.1074/jbc.272.21.13676
M3 - Article
C2 - 9153218
AN - SCOPUS:0030999576
SN - 0021-9258
VL - 272
SP - 13676
EP - 13682
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 21
ER -