We report here development of a novel gene trap method in zebrafish using the Tol2 transposon system. First, we established a highly efficient transgenesis method in which a plasmid DNA containing the Tol2 transposon vector and the transposase mRNA synthesized in vitro were coinjected into one-cell stage embryos. The transposon vector inserted in the genome could be transmitted to the F1 progeny at high frequencies, and regulated gene expression by a specific promoter could be recapitulated in transgenic fish. Then we constructed a transposon-based gene trap vector containing a splice acceptor and the GFP gene, performed a pilot screen for gene trapping, and obtained fish expressing GFP in temporally and spatially restricted patterns. We confirmed the endogenous transcripts were indeed trapped by the insertions, and the insertion could interfere with expression of the trapped gene. We propose our gene trap approach should facilitate studies of vertebrate development and organogenesis.

How the innate and adaptive immune systems cooperate in the natural history of allergic diseases has been largely unknown. Plant-derived allergen, papain, and mite allergens, Der f 1 and Der p 1, belong to the same family of cysteine proteases. We examined the role of protease allergens in the induction of Ab production and airway inflammation after repeated intranasal administration without adjuvants and that in basophil/mast cell stimulation in vitro. Papain induced papain-specific IgE/IgG1 and lung eosinophilia. Der f 1 induced Der f 1–specific IgG1 and eosinophilia. Although papain-, Der f 1–, and Der p 1–stimulated basophils expressed allergy-inducing cytokines, including IL-4 in vitro, basophil-depleting Ab and mast cell deficiency did not suppress the papain-induced in vivo responses. Protease inhibitor–treated allergens and a catalytic site mutant did not induce the responses. These results indicate that protease activity is essential to Ab production and eosinophilia in vivo and basophil activation in vitro. IL-33–deficient mice lacked eosinophilia and had reduced papain-specific IgE/IgG1. Coadministration of OVA with papain induced OVA-specific IgE/IgG1, which was reduced in IL-33–deficient mice. We demonstrated IL-33 release, subsequent IL-33–dependent IL-5/IL-13 release, and activation of T1/ST2-expressing lineage−CD25+CD44+ innate lymphoid cells in the lung after papain inhalation, suggesting the contribution of the IL-33–type 2 innate lymphoid cell–IL-5/IL-13 axis to the papain-induced airway eosinophilia. Rag2-deficient mice, which lack adaptive immune cells, showed significant, but less severe, eosinophilia. Collectively, these results suggest cooperation of adaptive immune cells and IL-33–responsive innate cells in protease-dependent allergic airway inflammation.

To provide a more comprehensive understanding of the genes and evolutionary forces driving colorectal cancer (CRC) progression, we performed Sleeping Beauty (SB) transposon mutagenesis screens in mice carrying sensitizing mutations in genes that act at different stages of tumor progression. This approach allowed us to identify a set of genes that appear to be highly relevant for CRC and to provide a better understanding of the evolutionary forces and systems properties of CRC. We also identified six genes driving malignant tumor progression and a new human CRC tumor-suppressor gene, ZNF292, that might also function in other types of cancer. Our comprehensive CRC data set provides a resource with which to develop new therapies for treating CRC.