Pp-FHY1 Is Essential for Pp-PHY1 Nuclear Transport in P. patens.
(A) Cryptogams contain FHY1-like proteins. Sequence alignment of FHY1-like proteins from monocots, dicots, gymnosperms, and cryptogams. Only regions of high sequence similarity are shown. The dashed line indicates nonaligned regions. aa, amino acids.
(B) RT-PCR analysis of Pp-fhy1 mutants. Pp-FHY1 was deleted in Pp-PHY1:YFP-expressing lines. Two independent Pp-fhy1 mutants were used for RT-PCR analysis and Pp-EF1α was used as a control. WT, the wild type.
(C) Light-induced nuclear transport of Pp-PHY1 depends on Pp-FHY1. Dark-adapted protonema filaments of P. patens wild type or Pp-fhy1 mutants expressing Pp-PHY1:YFP were fixed before microscopy analysis. Images were acquired before (dark control [D]) and after irradiation with either R light (10 min, 22 μmol m−2 s−1) or FR light (1 h, 18 μmol m−2 s−1). Arrows indicate nuclei. Immunoblot analysis shows Pp-PHY1:YFP levels in the different light conditions. Bars = 20 μm.