Rodlet cells in epidermal explant cultures of Lepomis Macrochirus

Sunfish rodlet cells were examined in vitro using a novel tissue explant system. Outgrowth of epidermal cell layers from explanted fish scales enabled both live cell videomicroscopy and immunocytochemical analysis of rodlet cells within the cell layer. Cells stained with fluorescent phallotoxin and antibody to tubulin showed that F‐actin is a component of the fibrous capsule that envelopes the cell and a microtubule network extends from the basal to apical ends of the cell interior. The fibrous capsule is also enriched for phosphotyrosine suggesting a potential signal‐transducing capability is present in this structure. Videomicroscopy analysis of live explant cultures demonstrated that rodlet cells are immobile and that interior structures are highly dynamic. Rodlet sacs can undergo extension and retraction, while intracellular particles can move rapidly within these cells. Fish scale tissue explants provide a useful system for analyzing the molecular composition and dynamic behavior of rodlet cells.