A nucleus-encoded factor, CRR2, is essential for the expression of chloroplast ndhB in Arabidopsis.
The chloroplast NDH complex, NAD(P)H dehydrogenase, reduces the plastoquinone pool non-photochemically and is involved in cyclic electron flow around photosystem I (PSI). A transient increase in chlorophyll fluorescence after turning off actinic light is a result of NDH activity. We focused on this subtle change in chlorophyll fluorescence to isolate nuclear mutants affected in chloroplast NDH activity in Arabidopsis by using chlorophyll fluorescence imaging. crr2-1 and crr2-2 (chlororespiratory reduction) are recessive mutant alleles in which accumulation of the NDH complex is impaired. Except for the defect in NDH activity, photosynthetic electron transport was unaffected. CRR2 encodes a member of the plant combinatorial and modular protein (PCMP) family consisting of more than 200 genes in Arabidopsis. CRR2 functions in the intergenic processing of chloroplast RNA between rps7 and ndhB, which is possibly essential for ndhB translation. We have determined the function of a PCMP family member, indicating that the family is closely related to pentatrico-peptide PPR proteins involved in the maturation steps of organellar RNA.
Hashimoto
Mihoko
M
Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan.
Endo
Tsuyoshi
T
Peltier
Gilles
G
Tasaka
Masao
M
Shikanai
Toshiharu
T
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics*; D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism*; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D008027:Light; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009154:Mutation; D009245:NADH Dehydrogenase / Q000235:genetics / Q000378:metabolism; D010788:Photosynthesis / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism
D029681:Arabidopsis Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D010940:Plant Proteins; C079008:ndhB protein, Arabidopsis; D002734:Chlorophyll; D009245:NADH Dehydrogenase