Location: Aquatic Animal Health ResearchTitle: Molecular characterization and gene expression of the channel catfish Ferritin H subunit after bacterial infection and iron treatment Author
Submitted to: Journal of Experimental Zoology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2010
Publication Date: 3/12/2010
Publication URL: http://handle.nal.usda.gov/10113/56892
Citation: Liu, H., Takano, T., Peatman, E., Abernathy, J., Wang, S., Sha, Z., Kucuktas, H., Xu, D., Klesius, P.H., Liu, Z. 2010. Molecular characterization and gene expression of the channel catfish Ferritin H subunit after bacterial infection and iron treatment. Journal of Experimental Zoology. 313A(6):359-368. Interpretive Summary: Ferritins are a group of proteins which play important roles in maintaining iron in a soluble, nontoxic, bioavailable form. Ferritin genes are composed of heavy (H) and light (L) chain subunits in mammals and the information on teleost ferritin genes is limited. The objective of this study was to characterize the ferritin H gene in channel catfish, to determine its genomic organization and copy numbers, to determine its patterns of tissue expression, and to establish if it is involved in defense responses of catfish after bacterial infection. The catfish ferritin H gene was highly expressed in various healthy tissues and significantly up-regulated in the liver after intraperitoneal injection of iron-dextran, Edwardsiella ictaluri or mixture of E. ictaluri and iron-dextran, suggesting its role in both iron metabolism and immunity. Since iron is vital to nearly all organisms in many metabolic pathways: oxygen transport, electron transport, and DNA synthesis, the results in this study will help to understand the complex functions of the ferritin genes in iron detoxification, iron storage, cellular defense against stress and inflammation, and immune response against pathogen infections.
Technical Abstract: Ferritins are the major iron storage protein in the cytoplasm of cells, responsible for regulating levels of intracellular iron. Ferritin genes are widely distributed in both prokaryotes and eukaryotes. In mammals, ferritin molecules are composed of heavy- (H) and light- (L) chain subunits; amphibian genomes contain three ferritin-type genes (H; middle,M; and L subunits); and teleost genomes to date contain H and M subunits. The object of this study was to characterize the ferritin H gene in channel catfish, to determine its genomic organization and copy numbers, to determine its patterns of tissue expression, and to establish if it is involved in defense responses of catfish after bacterial infection. The catfish ferritin H gene was completely sequenced and characterized, using both mRNA and genomic DNA. Catfish ferritin H gene has a full-length mRNA sequence of 999 bp, an open reading frame of 534bp, and 4,704bp genomic DNA sequence. Catfish ferritin H has a 5 exon and 4 intron genetic organization, containing a long 50-untranslated region, which shares high similarity with mammalian and zebrafish genes. Based on phylogenetic analyses, the catfish ferritin H gene is highly conserved throughout evolution. Southern blot analysis suggested that the ferritin H gene has only one copy in the catfish genome. The catfish ferritin H gene was widely expressed in various healthy tissues. The catfish ferritin H gene was significantly up-regulated in the liver after intraperitoneal injection of iron dextran and coinjection of Edwardsiella ictaluri and iron dextran treatment, suggesting its role in iron metabolism and immunity.