Fig. 6.

Inducible gene expression in diverse cell types using the Tet-On system. (A) Schematic of the transgenic activator and responder constructs used to induce GFP expression in S. purpuratus embryos (see Materials and Methods). (B,C) GFP expression in the PMCs of transgenic S. purpuratus (B) and L. variegatus (C) embryos exposed to 5 μg/ml Dox overnight at the late gastrula stage. GFP fluorescence was not observed when embryos were not exposed to Dox. Top: GFP fluorescence in live embryos. Bottom: GFP fluorescence overlaid onto DIC images. (D) GFP expression in different cell types of transgenic embryos exposed to 5 μg/ml Dox overnight at the late gastrula stage. The number of embryos with GFP fluorescence showing expression in the expected cell types was scored. Top: GFP fluorescence in live embryos. Bottom: GFP fluorescence overlaid onto DIC images. Scale bars: 50 μm.