Molecular Characterization And Expression Analysis Of Lectin-related Genes From Cynoglossus Semilaevis

Half-smooth tongue sole(Cynoglossus semilaevis)is an economically important farmed marine fish that are widely distributed along the Chinese coast.Because of its desirable taste and nutritional,it was selected for aquaculture and with highly economic value.At present,half smooth tongue sole has achieved factory farming and all artificial propagation.With the expansion of industry scale,a variety of disease about half smooth tongue sole has produced in recent years.Frequent outbreaks of disease can cause a large number of fish deaths and severely restrict the development of aquaculture.Disease has become a major obstacle to its development.It is an important method to solve the problem of fish disease by combining the traditional breeding technology with the modern division breeding technology to cultivate the newly high yield and disease resistant varieties.The lectin family is a kind of non-antibody protein or glycoprotein,which can combined with the specific carbohydrate and has the function of agglutinating cell,sedimenting polysaccharide and complex carbohydrate.Galectin is S-type lectin,as a kind of pattern recognition receptor can molecular recognize relevant pathogens specifically and participate in a series of biological immune activity indirectly like antibody opsonization,cytophagy,complement activation and death of microbes and so on.Recent studies have found that a new galactin-related protein,which is homologous with galectin but lacks the binding capacity of galactose.This study identified one novel galectin-related protein from the Cynoglossus semilaevis,designated as Cs GRP.The full-length c DNA was 785 bp with a 528 bp open reading frame encoding a putative protein of 176 amino acids.Genomic structural analysis revealed that Cs GRP consists of five exons and four introns.Cs GRP showed 68% similarity with Poecilia latipinna GRP and 67% similarity with Stegastes partitus GRP.q RT-PCR analysis showed that the expression level of Cs GRP was highest in the liver although its expression was detected in all tested tissues.When challenged with Vibrio harveyi,the expression of Cs GRP showed significantly decline in liver.In addition,we found that the Cp G island of Cs GRP showed higher methylation level in disease-resistant family of Cynoglossus semilaevis(DR-Cs)than in diseasesusceptible ones(DS-Cs).Our results suggest that Cs GRP,function as pattern recognition receptor,may play important roles in the immune response of Cynoglossus semilaevis.Moreover,DNA methylation patterns provide valuable data for understanding the relation of epigenetic regulation and immunity,which would assist the research of animal genetics and breeding in future.Vesicular-Integral membrane Protein of 36 ku(VIP36),belong to L-type lectin,responsible for the intracellular transport of glycoproteins within the secretory pathway and also can recognize high mannose-type glycans and participate in its transportation and classification.In this study,the full-length c DNA of two transcripts of VIP36,VIP36–X 1and VIP36-X2,were obtained and the related bioinformatics analyses were carried out.The evolutionary relationship of the gene between species were studied.Results of the expression of the two transcription m RNA in different tissues and different time periods after Vibrio harveyi challenged in Cynoglossus semilaevis showed that the expression level of the VIP36 gene was highest in the brian and lower in other immune tissues.The expression level of the VIP36-X1 after Vibrio harveyi challenged displays slightly upward trend,while there was no significant change in VIP36-X2 expression.These results indicate that VIP36 gene may play a weak role in immune modulation after Vibrio harveyi infection in.