Localization of rhodopsin by immunofluorescence microscope in Chlamydomonas reinhardtii

Using anti-rhodopsin antibody, an immunofluorescence method was established in Chlamydomonas reinhardtii in order to locate rhodopsin in the cell. The method showed that rhodopsin is located in the membrane near (or around) the pigmented eyespot in green algae. In synchronized cells, the location of rhodopsin changes regularly during the cell cycle. The fluorescence (F) spot moves from the anterior region toward the posterior region of the chloroplast (cp) in the light period. Following cell division, the F spots reappear in each daughter cell whether the daughter cells are released from the mother cell wall or not. The F spot is located opposite the site of the last cleavage furrow whether the cell has divided once, twice, or three times. The F spot moves back toward the anterior region from the equatorial plane after division in the dark period. In white algae eyespot-deficient mutants, rhodopsin does not depend on the presence of the eyespot. The results further showed that rhodopsin resides in the plasmalemma.