Trypsin-like Inhibitor Domain (TIL)-Harboring Protein Is Essential for Aedes aegypti Reproduction

Abstract

Cysteine-rich trypsin inhibitor-like domain (TIL)-harboring proteins are broadly distributed in nature but remain understudied in vector mosquitoes. Here we have explored the biology of a TIL domain-containing protein of the arbovirus vector Aedes aegypti, cysteine-rich venom protein 379 (CRVP379). CRVP379 was previously shown to be essential for dengue virus infection in Ae. aegypti mosquitoes. Gene expression analysis showed CRVP379 to be highly expressed in pupal stages, male testes, and female ovaries. CRVP379 expression is also increased in the ovaries at 48 h post-blood feeding. We used CRISPR-Cas9 genome editing to generate two mutant lines of CRVP379 with mutations inside or outside the TIL domain. Female mosquitoes from both mutant lines showed severe defects in their reproductive capability; mutant females also showed differences in their follicular cell morphology. However, the CRVP379 line with a mutation outside the TIL domain did not affect male reproductive performance, suggesting that some CRVP379 residues may have sexually dimorphic functions. In contrast to previous reports, we did not observe a noticeable difference in dengue virus infection between the wild-type and any of the mutant lines. The importance of CRVP379 in Ae. aegypti reproductive biology makes it an interesting candidate for the development of Ae. aegypti population control methods.

A Genome-Wide Analysis of Serine Protease Inhibitors in Cydia pomonella Provides Insights into Their Evolution and Expression Pattern

“…Based on a conserved-domain search, we found that the TIL domain was also present in serpins of nine other lepidopteran insects (A. transitella, D. plexippus, H. armigera, H. melpomene, M. cinxia, P. rapae, P. xuthus, S. litura, and T. ni) that were used for comparative genomics analysis. Previous studies have reported that the TIL domain-containing proteins are mainly involved in regulating the host immune response by inhibiting the protease cascade reaction [66][67][68] and by participating in the regulation of mosquito reproduction [69]; thus, we inferred that the function of CpSPN25 might be an immune inhibitor. As with the PRK13335 (annotated as superantigen-like protein 3 in the NCBI CDD) and PRK08581 (annotated as amidase domain-containing protein) superfamily domains, the former was only found in CpSPN26, while the latter was also detected in BmSPN27.…”