In vivo differentiation of rat pES cells. (a) F1 generation germline chimera pups ubiquitously expressed the venus gene in a rat ES cell line (rpESWIv2iF-5). (b) Venus expression patterns of main organs in rat pES-derived chimeric rat. Br, brain; Th, thymus; He, heart; Lu, lung; Li, liver; St, stomach; Pa, pancreas; Ki, kidney; Ut, uterus; Mu, muscle. Left: bright field, right: fluorescent image. Color images available online at www.liebertpub.com/scd