Tol2 Gene Trap Integrations in the Zebrafish Amyloid Precursor Protein Genes appa and aplp2 Reveal Accumulation of Secreted APP at the Embryonic Veins

Background—The single spanning transmembrane amyloid precursor protein (APP) and its proteolytic product, amyloid-beta (Aβ) peptide, have been intensely studied due to their role in the pathogenesis of Alzheimer’s disease. However, the biological role of the secreted ectodomain of APP, which is also generated by proteolytic cleavage, is less well understood. Here, we report Tol2 red fluorescent protein (RFP) transposon gene trap integrations in the zebrafish amyloid precursor protein a (appa) and amyloid precursor-like protein 2 (aplp2) genes. The transposon integrations are predicted to disrupt the appa and aplp2 genes to primarily produce secreted ectodomains of the corresponding proteins that are fused to RFP. Results—Our results indicate the Appa-RFP and Aplp2 fusion proteins are likely secreted from the central nervous system and accumulate in the embryonic veins independent of blood flow. Conclusions—The zebrafish appa and aplp2 transposon insertion alleles will be useful for investigating the biological role of the secreted form of APP

Combination of Reverse and Chemical Genetic Screens Reveals Angiogenesis Inhibitors and Targets

We combined reverse and chemical genetics to identify targets and compounds modulating blood vessel development. Through transcript profiling in mice, we identified 150 potentially druggable microvessel-enriched gene products. Orthologs of 50 of these were knocked down in a reverse genetic screen in zebrafish, demonstrating that 16 were necessary for developmental angiogenesis. In parallel, 1280 pharmacologically active compounds were screened in a human cell-based assay, identifying 28 compounds selectively inhibiting endothelial sprouting. Several links were revealed between the results of the reverse and chemical genetic screens, including the serine/threonine (S/ T) phosphatases ppp1ca, ppp1cc, and ppp4c and an inhibitor of this gene family; Endothall. Our results suggest that the combination of reverse and chemical genetic screens, in vertebrates, is an efficient strategy for the identification of drug targets and compounds that modulate complex biological systems, such as angiogenesis

Tol2 Gene Trap Integrations in the Zebrafish Amyloid Precursor Protein Genes appa and aplp2 Reveal Accumulation of Secreted APP at the Embryonic Veins

Background—The single spanning transmembrane amyloid precursor protein (APP) and its proteolytic product, amyloid-beta (Aβ) peptide, have been intensely studied due to their role in the pathogenesis of Alzheimer’s disease. However, the biological role of the secreted ectodomain of APP, which is also generated by proteolytic cleavage, is less well understood. Here, we report Tol2 red fluorescent protein (RFP) transposon gene trap integrations in the zebrafish amyloid precursor protein a (appa) and amyloid precursor-like protein 2 (aplp2) genes. The transposon integrations are predicted to disrupt the appa and aplp2 genes to primarily produce secreted ectodomains of the corresponding proteins that are fused to RFP. Results—Our results indicate the Appa-RFP and Aplp2 fusion proteins are likely secreted from the central nervous system and accumulate in the embryonic veins independent of blood flow. Conclusions—The zebrafish appa and aplp2 transposon insertion alleles will be useful for investigating the biological role of the secreted form of APP.This is the peer reviewed version of the following article: Liao, H.-K., Wang, Y., Noack Watt, K. E., Wen, Q., Breitbach, J., Kemmet, C. K., Clark, K. J., Ekker, S. C., Essner, J. J. and McGrail, M. (2012), Tol2 gene trap integrations in the zebrafish amyloid precursor protein genes appa and aplp2 reveal accumulation of secreted APP at the embryonic veins. Dev. Dyn., 241: 415–425, which has been published in final form at doi:10.1002/dvdy.23725. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving</p

Combination of Reverse and Chemical Genetic Screens Reveals Angiogenesis Inhibitors and Targets

We combined reverse and chemical genetics to identify targets and compounds modulating blood vessel development. Through transcript profiling in mice, we identified 150 potentially druggable microvessel-enriched gene products. Orthologs of 50 of these were knocked down in a reverse genetic screen in zebrafish, demonstrating that 16 were necessary for developmental angiogenesis. In parallel, 1280 pharmacologically active compounds were screened in a human cell-based assay, identifying 28 compounds selectively inhibiting endothelial sprouting. Several links were revealed between the results of the reverse and chemical genetic screens, including the serine/threonine (S/ T) phosphatases ppp1ca, ppp1cc, and ppp4c and an inhibitor of this gene family; Endothall. Our results suggest that the combination of reverse and chemical genetic screens, in vertebrates, is an efficient strategy for the identification of drug targets and compounds that modulate complex biological systems, such as angiogenesis.This is a manuscript of an article published as Kalén, Mattias, Elisabet Wallgard, Noomi Asker, Aidas Nasevicius, Elisabet Athley, Erik Billgren, Jon D. Larson et al. "Combination of reverse and chemical genetic screens reveals angiogenesis inhibitors and targets." Chemistry & biology 16, no. 4 (2009): 432-441. doi: 10.1016/j.chembiol.2009.02.010. Posted with permission.</p