title: Characterization of the psbH precursor RNAs reveals a precise endoribonuclease cleavage site in the psbT/psbH intergenic region that is dependent on psbN gene expression.
abstract: The plastid psbB operon harbours 5 genes, psbB, psbT, psbH, petB and petD. A sixth gene, the psbN gene, is located on the opposite DNA strand in the psbT/psbH intergenic region. Its transcription produces antisense RNA to a large part of the psbB pentacistronic mRNA. We have investigated whether transcription of the psbN gene, i.e. production of antisense RNA, influences psbT/psbH intergenic processing. Results reveal the existence of four different psbH precursor RNAs. Three of them result from processing and one is produced by transcription initiation. One of the processed RNAs is probably created by site-specific RNA cleavage. This RNA is absent in plants where the psbN gene is not transcribed suggesting that cleavage at this site is dependent on the formation of sense/antisense double-stranded RNA. In order to characterize the nuclease that might be responsible for double-stranded RNA cleavage, we analysed csp41a and csp41b knock-out mutants and the corresponding double mutant. Both CSP41 proteins are known to interact physically and CSP41a had been shown to cleave within 3'-untranslated region stem-loop structures, which contain double-stranded RNA, in vitro. We demonstrate that the psbH RNA, that is absent in plants where the psbN gene is not transcribed, is also strongly diminished in all csp41 plants. Altogether, results reveal a site-specific endoribonuclease cleavage event that seems to depend on antisense RNA and might implicate endoribonuclease activity of CSP41a.
authors.affiliation: Laboratoire Physiologie Cellulaire Végétale, UMR 5168, CNRS, Grenoble, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Chevalier
authors.forename: Mustafa Malik
authors.initials: MM
authors.lastname: Ghulam
authors.forename: Damien
authors.initials: D
authors.lastname: Rondet
authors.forename: Thomas
authors.initials: T
authors.lastname: Pfannschmidt
authors.forename: Livia
authors.initials: L
authors.lastname: Merendino
authors.forename: Silva
authors.initials: S
authors.lastname: Lerbs-Mache
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002736:Chloroplasts / Q000235:genetics* / Q000378:metabolism; D021901:DNA, Intergenic; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D017343:Genes, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics*; D045332:Photosystem II Protein Complex / Q000235:genetics*; D030821:Plants, Genetically Modified; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D016372:RNA, Antisense / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D021901:DNA, Intergenic; D010750:Phosphoproteins; D045332:Photosystem II Protein Complex; D012322:RNA Precursors; D016372:RNA, Antisense; D018749:RNA, Plant; C063224:photosystem II, psbH subunit; D004722:Endoribonucleases; C106104:endoribonuclease CSP41