Figure 7.

Under Conditions of D1 Repair Synthesis, the psbA mRNA Colocalized with Thylakoids and Translation Components throughout the Chloroplast.

(A) to (D) DA cells were exposed to HL for 10 min (HL10′ cells) to induce PSII photodamage and D1 repair synthesis and then FISH-probed for the psbA mRNA and concurrently IF-stained for the thylakoid marker protein PsaA (100%; n = 20) (A), the r-protein of the 30S subunit of the chloroplast ribosome (100%; n = 20) (B), the RNA binding protein RB38 (100%; n = 20) (C), or the rbcL mRNA (D).

(E) to (H) Cells were IF-stained for the r-protein of the 30S chloroplast ribosomal subunit and co-FISH-probed for the psbC mRNA ([E] and [F]) or the psbA mRNA ([G] and [H]). The psbA and psbC mRNAs colocalized with the 30S ribosomal subunit r-protein in T zones during the induction of PSII assembly in DA cells that were exposed to HL for 1 min ([E] and [G], respectively). Distinct localization of the psbA and psbC mRNAs during the D1 repair synthesis was induced during a subsequent 5-min incubation under ML ([E] and [G], respectively).

The percentage of cells with the localization patterns seen in each image set (and described in the text) and the number of cells examined (n) are given above. The fourth column shows merged images in which the pixels with the strongest colocalized signals are highlighted in white. Each image shows a 0.2-μm optical section. Bars = 1.0 μm.