Abstract: 【Aim】 To identify LY domain-containing trypsin (LY-trypsin) genes of Anopheles sinensis at the whole genome, and to explore their molecular characteristics, expression patterns and phylogentic relationships. 【Methods】 The amino acid sequences encoded by trypsin genes in An. gambiae, Aedes aegypti, Drosophila melanogaster, and Culex quinquefasciatus were downloaded from NCBI databases and used as queries to search for trypsin genes in An. sinensis genome using the local Blast program. LY-trypsin genes in An. sinensis were named based on domain characteristics and phylogenetic relationship. The structure, scaffold location, structural domain and phylogenetic relationships of LY-trypsin genes of An. sinensis, and their expression patterns at different developmental stages of An. sinensis, in different adult tissues of An. sinensis, and in female adults of An. sinensis before and after blood feeding were predicted using bioinformatics analysis. 【Results】 Twenty-seven LY-trypsin genes were identified in the whole genome of An. sinensis, while no LY-trypsin gene was identified in D. melanogaster, An. gambiae, C. quinquefasciatus, and A. aegypti. The 27 LY-trypsin genes of An. sinensis encode 329-1 125 amino acids, with the molecular weight of 36.8-125.5 kD, and pI of 4.73-8.94. Among them 20 LY-trypsin proteins have signal peptides, with their length ranging from 10 to 62 aa. The numbers of exons of the 27 LY-trypsin genes of An.sinensis range from one to five, and the length of introns ranges from 62 to 20 093 bp. The 27 LY-trypsin genes of An.sinensis are mapped on 11 scaffolds, their encoded proteins all have a conserved YWTD motif (LY motif), and the amino acid sequences encoded by 16 LY-trypsin genes of the 27 LY-trypsin genes have the active site containing the catalytic triad of serine, histidine and aspartic acid. Phylogenetic results showed that the 27 LY -trypsin genes of An. sinensis clustered into four branches. At different developmental stages, more than 50% of the LY-trypsin genes of An. sinensis showed similar expression patterns and were expressed at high levels during the larval stage. LY-trypsin genes were expressed in different adult tissues of An. sinensis. Only a few of LY-trypsin genes were expressed in female adults of An. sinensis before and after blood feeding without expression specificity. 【Conclusion】 In this study, LY-trypsin genes have been identified in the genome of An. sinensis for the first time, and the molecular characteristics and expression patterns of the LY-trypsin genes have been investigated. This study provides an information framework for the further study of LY-trypsin genes.

Key words: Anopheles sinensis, trypsin gene, LY domain, genome, expression pattern, phylogeny