Fig 2. Upk3a^GCE/+ drives conditional expression of the human AR transgene in mouse bladder urothelium.

(A) Schematic depicting the Cre/LoxP-mediated recombination, resulting in deletion of the STOP cassette from the R26AR transgene allele. (B) Experimental set-up for tamoxifen-induced human AR transgene expression. (C) Genomic PCR analyses of recombination events with specific primers for the human AR transgene allele (see Fig 2A) with bladder urothelium tissue samples of R26AR^LoxP/+Upk3a^GCE/+ and R26AR^LoxP/+ mice. The AR trangene allele was detected in the samples of both R26AR^LoxP/+Upk3a^GCE/+ and R26AR^LoxP/+ mice (black arrow), but TM induced recombination on the AR transgene allele was only observed in R26AR^LoxP/+Upk3a^GCE/+ mice (white arrow). (D-F’) Immunohistochemical staining of the bladder urothelium of TM injected R26AR^LoxP/+ mice using either the antibody that is reactive to both mouse and human AR protein (m&hAR), or the antibody that is reactive to only human AR (hAR) (n = 9). (F-G’) Immunohistochemical staining of the bladder urothelium with the two different AR antibodies as described above using the samples of TM-injected R26AR^LoxP/+Upk3a^GCE/+ mice (n = 12). (H-K”) Single channel and merged immunofluorescent images of bladder tissues of TM-injected R26AR^LoxP/+ and R26AR^LoxP/+Upk3a^GCE/+ mice stained with antibodies against CK5 p63, and the human AR (in red) (n = 6).