Fig. 1

(A) Diagram of the tetracyline-inducible Wnt4 transgene cassette. (more details are given in the results section) (B) Expression of Wnt4 and the luciferase reporter is regulated by doxycycline. 293T cells stably expressing rtTA were transfected with either TMILA-Wnt4 vector or parental TMILA vector. Transfected cells were incubated for 24 hrs with or without doxycycline (1 μg/ml), and cell lysates were prepared to measure luciferase activity. Expression of Wnt4 protein was assessed through Western blot analysis using a mouse Wnt4-specific antibody. (C) Southern blot analysis of tet-Wnt4 transgenic mice. Genomic DNA from a non-transgenic mouse was used as a negative control and spiked with TMILA-Wnt4 vector fragment to determine the approximate copy number of the integrated transgene (probes and digestion as described in Methods).