Figure 7.

Relocation of Ycf1 in nucleus restores biogenesis of NADH dehydrogenase (NDH), photosystem I (PSI) and cytochrome b₆f (Cytb₆f) in pbr1-1. (a) Phenotypes of 16-day-old plants of the wild-type (WT), pbr1-1, two allotopic-expression lines of Ycf1 (YA-9 and YA-16) and complemented pbr1-1 with genomic DNA of PBR1 (pbr1-1 Comp). (b, c) Allotopic expression analysis of Ycf1 fused with the plastid-transit peptide sequence of the nuclear-encoded rbcS gene (rbcS-TP-Ycf1) by reverse transcriptase–PCR in leaves of the indicated genotypes. The specific primers derived from the plastid-transit sequence of rbcS and coding region of Ycf1 were used to amplify the transcripts of rbcS-TP-Ycf1 from the nucleus. (d) Protein levels of Ycf1 in leaves of the WT, pbr1-1 and YA-9 plants detected by western blots. (e) Transmission electron micrographs of chloroplasts from the indicated genotypes. (f) Analysis of thylakoid membrane protein complexes by Blue-Native polyacrylamide gel electrophoresis (BN-PAGE). Equal amounts of samples (3 μg chlorophyll) were separated. Red arrows indicate the restoration of corresponding complexes in pbr1-1 mutant by allotopic expression of Ycf1 or genomic complementation. (g) Immunodetection of thylakoid complex proteins. The blots were probed with antibodies against the indicated proteins, respectively. SDS-PAGE, sodium dodecyl sulfate PAGE.