Northern analysis of AC133 antigen mRNA expression. (A) Total RNA was extracted from HeLa cells, Y79 cells, PMA-activated Y79 cells, WERI-Rb-1 cells, and MACS-isolated AC133⁺ fetal liver cells. Each lane was loaded with 15 μg total RNA, and a ³²P-labeled 800-bp cDNA fragment was used as a probe. (B) Multiple tissue poly A+ Northern blots were purchased from Clontech and probed with 32P-AC133 antigen cDNA.