This dominant negative effect is likely a result of the efficient base pairing of the HybU7/Δ8 snRNA to dH3/2m-3′B pre-mRNA and the inability of mammalian Lsm11 and FLASH to recruit Drosophila HCC required for forming a productive semi-recombinant holo U7 snRNP. The gene discussed is U7; the disease is hepatocellular carcinoma.