Localization of CGHR family proteins in P. tricornutum. (A) SIM images of P. tricornutum mutants expressing Pt43234:GFP, Pt43232:GFP, or Pt32401:GFP. The light image (Left), merged image (Center), and magnified merged image (Right) are shown. (Scale bars, 5 μm.) The GFP signal was likely located at the surface or outside the chloroplast in all images. (B) Immunogold labeling TEM images of P. tricornutum cells expressing Pt43234:GFP, Pt43233:GFP, Pt43232:GFP, or Pt32401:GFP. Only Pt43233:GFP was targeted to the pyrenoid-penetrating thylakoid; however, in contrast, Pt43234:GFP was targeted to the mitochondria; Pt43232:GFP was targeted at the space between the chloroplast and the vacuole; and Pt32401 was targeted at the space between the mitochondria and the chloroplast. Arrows are used to represent gold particles. Ch, chloroplast; Mt, mitochondria; N, nucleus; pTk, pyrenoid-penetratng thylakoid; Py, pyrenoid; Tk, thylakoid; V, vacuole.