Ribosomal RNA processing and an RNase R family member in chloroplasts of Arabidopsis.
An Arabidopsis mutant rnr1 , which has a defect in the basic genetic system in chloroplasts, was isolated using the screening of the high chlorophyll fluorescence phenotype. Whereas chlorophyll fluorescence and immunoblot studies showed the mutant had reduced activities of photosystems I and II, molecular characterization of the mutant suggested that a T-DNA insertion impaired the expression of a gene encoding a RNase R family member with a targeting signal to chloroplasts. Since RNase R family members have a 3'-5' exoribonuclease activity, we examined the RNA profile in chloroplasts. In rnr1 the intercistronic cleavage between 23S and 4.5S rRNA was impaired, and a significant reduction in rRNA in chloroplasts was found, suggesting that RNR1 functions in the maturation of chloroplast rRNA. The present results suggest that defects in the genetic system in chloroplasts cause high chlorophyll fluorescence, pale green leaf, and marked reduction in the growth rate, whereas the levels of some chloroplast RNA were higher in rnr1 than in the wild-type.
Kishine
Masahiro
M
Graduate School of Biostudies, Kyoto University, Japan.
Takabayashi
Atsushi
A
Munekage
Yuri
Y
Shikanai
Toshiharu
T
Endo
Tsuyoshi
T
Sato
Fumihiko
F
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism; D002736:Chloroplasts / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004579:Electron Transport / Q000235:genetics; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism*; D005095:Exoribonucleases; D005453:Fluorescence; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009154:Mutation; D010788:Photosynthesis / Q000235:genetics / Q000502:physiology; D014176:Protein Biosynthesis; D012323:RNA Processing, Post-Transcriptional; D018747:RNA, Chloroplast / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D018747:RNA, Chloroplast; D012335:RNA, Ribosomal; D011993:Recombinant Fusion Proteins; D002734:Chlorophyll; D049452:Green Fluorescent Proteins; D004722:Endoribonucleases; D005095:Exoribonucleases; C080868:ribonuclease R