Northern analysis of murine AC133 antigen mRNA expression. Multiple tissue poly A⁺ Northern blots were purchased from Clontech (San Diego, CA) and probed with³²P murine AC133 antigen cDNA. (A) Expression of message is detectable in mouse embryo peaking at day 11, and then tapering off to still detectable levels at days 15 and 17. (B) In adult tissues, message is detectable in brain, lung, skeletal muscle, kidney, and testis.