In silico Identification and in vivo Validation of Sialyltransferase Enzymes in Some Insect Species
Project no. 23087 · Status: Kapanmış · 2021
Summary
Sialyltransferases are enzymes that transfer sialic acids from CMP- N-acetylneuramic acid (CMP-ß-Neu5Ac) to galatose (Gal), N-acetylglucosamine (N-GlcNAc), N-acetylgalactosamine (N-GalNAc) glycans located at the ends of glycoconjugates. These enzymes transfer sialic acids to glycoconjugates via ?2-3, ?2-6, and ?2-8 glycosidic links. Sialyltransferases divided 4 groups by glycosidic links: ß-galactoside ?2,3-sialyltransferase (ST3Gal I-VI), ß-galactoside ?2,6-sialyltransferase (ST6Gal I-II), N-acetylgalactosamine ?2,6- sialyltransferase (ST6GalNAc I-VI), ?2,8-sialyltransferase (ST8Sia I-VI). 20 sialyltransferases are known in the vertebrate genome. Studies in invertebrates are scarce, so sialyltransferase motif sequences (sialylmotif L (large), sialylmotif S (small), sialylmotif VS (very small) and sialylmotif III) in transcriptome (all mRNA sequences), obtained from genome databases of insects, will be determined by computational methods and sialyltransferases in insects defined. It is aimed to reveal the similarities between the three-dimensional structures of sialyltransferase enzymes in mammals. In addition, Bombyx mori ST6Gal I sialyltransferase gene expression determined with Real-time PCR by feeding with sialic acid leaves. As a result of the bioinformatics studies, these motifs were found only in Manduca sexta and Galleria mellonella species. The possibility of this is very important for future studies and evolution. The sequence found in M. sexta was similar to ST6GalNAc I in vertebrates. The sequence found in G. mellonella was similar to ST3Gal IV in vertebrates. Looking at the Real-time PCR results, ST6Gal I gene expression levels are different in different tissues and in different stages of silkworm (B. mori). Among the tissues treated with sialic acid, the highest expression level of ST6Gal I was observed in fat body. This information is a sign for further studies on sialyltransferases in invertebrates. As the genome determined insects were studied, new sequences for the sialyltransferase enzyme will appear. This shows, there should be future studies about evolutionary point of sialyltransferases.