Date: Saturday, January 14, 2012
Time: 11:20 AM
Time: 11:20 AM
Room: Royal Palm Salons 3-4
L-type lectins are intracellular lectins that are located in luminal compartments of the secretary pathway with mannose-binding selectivity, and play crucial roles in selective protein trafficking, sorting and targeting. This class of lectins includes the 53 kDa endoplasmic reticulum ER-Golgi intermediate compartment protein (ERGIC-53), and the vesicular integral protein of 36 kDa (VIP36), and the VIP36-like protein. In spite of their importance, research on the L-type lectin of teleost fish has been largely lacking. In this study, we cloned three L-type lectins, the ERGIC-53, VIP36, and VIP36-like from channel catfish, Ictalurus punctatus. Phylogenetic analysis indicated that the catfish genes are orthologous to their counterparts in other species, however, several teleost fish appeared to have a duplicate of VIP36-like gene, which was not found to be duplicated in the channel catfish genome; all three genes are single copy gene 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 different strong tissue preference of expression. Upon infection with Edwardsiella ictaluri, expressions of the three genes all had significant up-regulation in the head kidney, but have distinct expression patterns: ERGIC-53 was gradually induced with the most highly induced expression 7 days after challenge in the head kidney; VIP36 was highly induced in the head kidney, and 3 days after challenge in the brain; VIP36-like gene appeared to be up-regulated, but it was only apparent at 4 hours after challenge in the spleen. This pattern of expression indicates that all three lectin genes may be involved in the immune responses of catfish after infection with ESC, and that the immune and endocrine systems are a complex regulatory network to ensure the homeostasis during the health or stress state of animal.