Analysis of Abcg5 expression. a, PCR products were obtained from cDNA synthesized from RNA extracted from different human tissues. A correctly spliced 250-bp fragment is expected for detection of expression (indicated by arrow), compared with a genomic fragment of 838 bp (compare cloned cDNA fragment, track 4, with genomic DNA fragment, track 3). A number of other PCR products were also consistently obtained, but did not contain ABCG5 sequence. b, Tissue expression of mouse Abcg5 was analyzed by northern-blot analysis. An expected 2.5-kb message was detected, with a fainter band of about 3.5 kb, in liver and small intestine only (tracks 4 and 8).