Cloning And Sequence Analysis Of The CD109 Gene In Lamprey

The CD109 gene is a member of theα2-macroglobulin/complement C3, C4, C5 (AMCOM) gene family and encodes a glycosylphosphatidylinositol(GPI)-anchored cell surface protein that contains a thioester domain. There were reports on that CD109 was observed up-regulated in some tumors. Thus, CD109 could be used as a typical marker for the diagnosis of some tumors. On the protein structure, the relationship between structure and function, the phylogenetics, the function in the normal cells and tissues and the role in tumor occurrence and development remains to be further study.The lamprey is a typical one of the oldest class of vertebrates without jaws, is considered to be in adaptive immune system evolved out of the edge, is a good model orgasm. There were no reported CD109 of lamprey. So the research on CD109 of lamprey can provide reference about the structure and function as well as mechanisms.Inthis study, based on the lamprey leukocytes EST, obtain the full-length sequence of lamprey CD109 cDNA, and build the prokaryotic expression vector. Using bioinformatics network resources and relevant softwares, we predict that lamprey CD109 cDNA has a 4218bp open reading frame(ORF) flanked by a 114bp 5'UTR and a 652bp 3'UTR. The deduced amino acid sequence has 1405 residues, which contains a signal peptide, a thioester motif, GPI-anchor cleavage site, 16 potential N-glycosylation sites, no typical hydrophobic regions and transmembrane region. Construction of evolutionary tree results showed that the lamprey CD109 has the nearest relationship. Function prediction result show that the protein involved in cell immune response. These experimental results and prediction lay the foundation for the further study on CD109.