Thrikawala, S. | Search bioRxiv

bioRxiv2026

Cp36 serine recombinase as a new tool for zebrafish transgenesis

One feature key to the versatility of zebrafish as an animal model for biomedical research is the breadth of genetic tools available, including for transgenesis. While the Tol2 transposase system remains the gold standard, its efficiency can be highly variable. Here, we explored the potential of a complementary transgenesis system, Cp36, a large serine recombinase identified from Clostridium perfringens previously found to efficiently integrate target cargo into the human genome without a preinstalled attB site. We generated Cp36-based plasmid constructs for zebrafish transgenesis and compared their performance to matched Tol2 plasmids across multiple experimental contexts, including transient expression, germline transmission, and multi-transgene expression. Cp36 integrates small [~]3.5kb cargo into the zebrafish genome and transmits to the next generation as efficiently as Tol2, but Cp36 performance declines substantially for larger [~]7.5kb constructs. Both Cp36 and Tol2 have comparable efficiency in transiently expressing a second construct regardless of the transposase/recombinase used to integrate the first construct, indicating compatibility with sequential transgenesis strategies. In summary, we demonstrate that Cp36 functions as a new alternative transgenesis method in zebrafish.

genetics↗

bioRxiv2021

Cyclooxygenase production of PGE2 promotes phagocyte control of A. fumigatus hyphal growth in larval zebrafish

Invasive aspergillosis is a common opportunistic infection, causing >50% mortality in infected immunocompromised patients. The specific molecular mechanisms of the innate immune system that prevent pathogenesis of invasive aspergillosis in immunocompetent individuals are not fully understood. Here, we used a zebrafish larva-Aspergillus infection model to identify cyclooxygenase (COX) enzyme signaling as one mechanism that promotes host survival. Larvae exposed to the pan-COX inhibitor indomethacin succumb to infection at a significantly higher rate than control larvae. COX signaling is both macrophage- and neutrophil-mediated. However, indomethacin treatment has no effect on phagocyte recruitment. Instead, COX signaling promotes phagocyte-mediated inhibition of germination and invasive hyphal growth. Protective COX-mediated signaling requires the receptor EP2 and exogenous prostaglandin E2 (PGE2) rescues indomethacin-induced decreased immune control of fungal growth. Collectively, we find that COX signaling activates the PGE2-EP2 pathway to increase control A. fumigatus hyphal growth by phagocytes in zebrafish larvae. Author SummaryInvasive aspergillosis causes mortality in >50% of infected patients. It is caused by a free-living fungus Aspergillus fumigatus which releases thousands of airborne spores. While healthy individuals clear inhaled spores efficiently, in immunocompromised individuals these spores grow into filamentous hyphae and destroy lungs and other tissues causing invasive aspergillosis. The immune mechanisms that control this fungal growth in healthy people are still largely unknown. Here, we used a larval zebrafish model of A. fumigatus infection to determine that cyclooxygenase enzymes, which are the target of non-steroidal anti-inflammatory drugs such as aspirin and ibuprofen, are important to control the fungus. Innate immune cells use cyclooxygenase signaling to prevent hyphal growth and tissue destruction. Our study provides new insights into the mechanisms that immune cells deploy to stop invasive growth of A. fumigatus and inform development of future strategies to combat invasive aspergillosis.

immunology↗