RT-PCR analysis of wt1MO embryos. RNA from buffer (b) injected and (m) wt1MO injected embryos was used as a template in a RT-PCR designed to amplify a portion of the wt1 messenger RNA at 48 hpf or 4 dpf. Most of the mRNA amplified in the morpholino injected embryos is aberrantly spliced yielding a smaller PCR product (arrow) than in wild type (arrowhead). M: 100 base pair ladder. Some wild type message is still present in the morpholino-injected embryos.