Figure 1.
Establishment and maintenance of cell polarity in monospores from the red alga P. yezoensis. (A) Discharge of unicellular monospores from a multicellular gametophytic blade of P. yezoensis strain TU-1. Scale bar = 20 µm. (B–D) Asymmetrical distribution of F-actin during early development of monospores. F-actin was stained with alex Flour 488 phalloidin. (B) Discharged monospore. (C) Migrating monospore. (D) Adhering monospore. Upper and lower photos in each panel show bright-field and fluorescent images, respectively. Arrow in (C) indicates the direction of migration. Scale bars = 5 µm. (e) Schematic representation of our working hypothesis about the formation of cell polarity required for monospore migration. Photosynthesis-dependent [Ca2+]cyt increase regulates PLC and PI3K for the establishment of cell polarity, while PLD is required for the maintenance of the established cell polarity. DG, diacylgycerol; IP3, inositol-1,4,5-trisphosphate; IP3r, IP3 receptor; PC, phosphatidylcholine.