Location: Warmwater Aquaculture Research UnitTitle: Molecular responses of calreticulin genes to iron overload and bacterial challenge in channel catfish Ictalurus punctatus) Author
|Waldbieser, Geoffrey - Geoff|
Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2010
Publication Date: N/A
Publication URL: http://handle.nal.usda.gov/10113/55491
Citation: Interpretive Summary: Commercial catfish producers experience significant losses due to disease in earthen pond culture. In order to better understand the molecular mechanisms that underlie catfish immunity, three calreticulin genes were identified in the catfish genome. Experimental challenges with a bacterial pathogen demonstrated these genes are actively transcribed during infection. This research provides the basis for further investigation into the role of calreticulin genes in catfish immune responses and their potential as biomarkers for catfish health.
Technical Abstract: Infection and inflammation are often accompanied by oxidative stress caused by the accumulation of reactive oxygen species which can be deleterious to the health of the host. Antioxidant defense mechanisms and components are crucial in limiting cellular and tissue-level damage and restoring homeostasis. In mammals, calreticulin is a 46-kDa multifunctional calcium binding protein of the endoplasmic reticulum that has many critical functions in the eukaryotic cell including regulation of intracellular calcium homoeostasis, lectin binding and chaperoning, and oxidative stress responses. In previous studies from our lab, the calreticulin gene was observed to be strongly upregulated in catfish during challenge with infectious Gram-negative bacteria. However, little is known about the function of this gene in teleost fish. The objective of this study, therefore, was to characterize the calreticulin gene from channel catfish, to determine its genomic organization, to profile its patterns of tissue expression, and to establish its potential for physiological antioxidant and immune responses in catfish after bacterial infection with Edwardsiella ictaluri and iron treatment. Our results indicate that there are at least three calreticulin related genes in the catfish genome. The three calreticulin genes are widely expressed in various tissues under homeostatic conditions and their expression showed significant upregulation following infection and/or iron level changes.