IMMUNOLOCALIZATION OF CYTOSOLIC PHYTOCHROME IN THE GREEN-ALGA MOUGEOTIA

The monoclonal antibody Z-3Bl (Schneider-Poetsch et al., Planta 173 [1988] 61-72) was used to localize phytochrome in the Mougeotia cell by indirect immunofluorescence. The antibody detected a protein of about 110 kD in the immunoblot. Immunofluorescence indicated abundant phytochrome throughout the cytoplasm. In Mougeotia, a large cytoplasmic pool of phytochrome is presumably in equilibrium with a probably reactant-bound P(fr)-pool at the plasmalemma, the latter being responsible for the physiological response.