title: Molecular characterization of three L-type lectin genes from channel catfish, Ictalurus punctatus and their responses to Edwardsiella ictaluri challenge.
abstract: L-type lectins have a leguminous lectin domain and can bind to high-mannose type oligosaccharides. In the secretory pathway, L-type lectins play crucial roles in selective protein trafficking, sorting and targeting. Three L-type lectins were cloned in the channel catfish, Ictalurus punctatus, the 53 kDa endoplasmic reticulum ER-Golgi intermediate compartment protein (ERGIC-53), the vesicular integral protein of 36 kDa (VIP36) and VIP36-like. Phylogenetic analysis indicated that the catfish genes are orthologous to their counterparts in other species. Southern blot analysis demonstrated that all three L-type lectin genes are likely single-copy genes in the catfish genome. Analysis of expression in healthy tissues using quantitative real time RT-PCR indicated that all three genes are expressed widely in all tested tissues, but with strong tissue preference of expression: ERGIC-53 was found to be abundantly expressed in the liver, VIP36 was found to be abundantly expressed in the head-kidney, whereas VIP36-like was found to be abundantly expressed in the brain. Upon infection with Edwardsiella ictaluri, expressions of the three genes all had significant up-regulation in the head-kidney, but had distinct expression patterns: ERGIC-53 was gradually induced with the highest expression 7 days after challenge in the head-kidney, but was down-regulated in the liver, spleen, and brain. VIP36 was highly induced in the head-kidney, and 3 days after challenge in the brain, but was not up-regulated in any other tissues or timepoints after challenge. Expression levels of the catfish VIP36-like gene appeared to also respond to infection, albeit with differing patterns among the tested tissues. Taken together, our results indicate that all three L-type lectin genes may be involved in the immune responses of catfish after infection with E. ictaluri.
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Eric
authors.initials: E
authors.lastname: Peatman
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Tingting
authors.initials: T
authors.lastname: Feng
authors.forename: Liqiao
authors.initials: L
authors.lastname: Chen
authors.forename: Zhanjiang
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020610:Edwardsiella ictaluri; D004756:Enterobacteriaceae Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D005786:Gene Expression Regulation / Q000276:immunology*; D007059:Ictaluridae; D037102:Lectins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D037102:Lectins