RESUMO
Objective: To identify the yellow family genes in Aedes aegypti and analyze the gene structure, phylogenetic evolution and their expression at various developmental stages and in different tissues. Methods: The yellow gene family was identified in Ae. aegypti by blasting the Ae. aegypti genome database with the amino acid sequence of the MRJP domain of Dm-yellow gene of Drosophila melanogasterï¼GenBank No. AAF45497ï¼. The physico-chemical property and domains were analyzed with the on-line ExPaSy software. The signal peptide was predicted using SignalP4.1 software. Sequence alignment and the phylogenetic tree were made through combined use of DNAstar, MEGA6.0 and GeneDoc. Total RNA was extracted from Ae. aegypti, cDNA was generated, and expression of the yellow family genes at various developmental stages ï¼egg, first to fourth instar, pupa, non-blood-fed female and male mosquitoesï¼ and in different tissues ï¼salivary gland, midgut, fat body, and ovaryï¼ was quantified using qRT-PCR. Results: Twelve yellow genes were identified from Ae. aegypti genome: Aa-yellow, Aa-yellow-b, Aa-yellow-c, Aa-yellow-d, Aa-yellow-e, Aa-yellow-f2, Aa-yellow-fb, Aa-yellow-fc, Aa-yellow-g, Aa-yellow-g2, Aa-yellow-h, and Aa-yellow-x. Bioinformatics demonstrated that all covered the MRJP domain and a signal peptide sequence. Sequence alignment revealed low ï¼15%-49%ï¼ homology among the proteins, but high homologyï¼60%ï¼ in the conserved domain. According to the phylogenetic tree analysis, the encoded 12 YELLOW proteins were classified into 5 subfamilies, and 11 had orthologues in D. melanogaster. qRT-PCR revealed high expression of Aa-yellow-d ï¼0.018 9ï¼ and Aa-yellow-x ï¼0.023 5ï¼ in male Ae. aegypti ï¼P<0.01 or P<0.05ï¼; high expression of Aa-yellow-fc ï¼0.024 8, 0.034 9ï¼ in female Ae. aegypti and in the salivary gland ï¼P<0.01ï¼; high expression of Aa-yellow-f2 ï¼0.093 4ï¼ in the second instar stage ï¼P<0.01ï¼; high expression of Aa-yellow ï¼0.562 1ï¼, Aa-yellow-e ï¼0.004 4ï¼, and Aa-yellow-fb ï¼0.008 4ï¼ in the third instar stage ï¼P<0.05ï¼; and high expression of Aa-yellow ï¼0.569 4ï¼, Aa-yellow-e ï¼0.027 0ï¼, Aa-yellow-f2 ï¼0.006 5ï¼, Aa-yellow-fb ï¼0.001 0ï¼, Aa-yellow-h ï¼0.084 8ï¼ and Aa-yellow-x ï¼0.015 1ï¼ in the ovary. Genes other than Aa-yellow-c ï¼0.004 0ï¼ and Aa-yellow-x ï¼0.007 4ï¼ were hardly expressed in the midgut. Conclusion: The 12 yellow genes identified in the Ae. aegypti genome have low homology, and are differentially expressed at different developmental stages and in tissues.
