Molecular cloning, differential expression and 3D structural analysis of the MHC class-II β chain from sea bass (Dicentrarchus labrax L.)
Author(s)
Date Issued
2007
Type
Article
Abstract
The major histocompatibility complex class I and II molecules (MHC-I and MHC-II) play a pivotal role in vertebrate immune
response to antigenic peptides. In this paper we report the cloning and sequencing of the MHC class II b chain from sea bass (Dicentrarchus
labrax L.). The six obtained cDNA sequences (designated as Dila-DAB) code for 250 amino acids, with a predicted 21
amino acid signal peptide and contain a 28 bp 50-UTR and a 478 bp 30-UTR. A multiple alignment of the predicted translation of the
Dila-DAB sequences was assembled together with other fish and mammalian sequences and it showed the conservation of most
amino acid residues characteristic of the MHC class II b chain structure. The highest basal Dila-DAB expression was found in gills,
followed by gut and thymus, lower mRNA levels were found in spleen, peripheral blood leucocytes (PBL) and liver. Stimulation of
head kidney leukocytes with LPS for 4 h showed very little difference in the Dila-DAB expression, but after 24 h the Dila-DAB
level decreased to a large extent and the difference was statistically significant. Stimulation of head kidney leukocytes with different
concentrations of rIL-1b (ranging from 0 to 100 ng/ml) resulted in a dose-dependent reduction of the Dila-DAB expression. Moreover,
two 3D Dila-DAB*0101 homology models were obtained based on crystallographic mouse MHC-II structures complexed
with D10 T-cell antigen receptor or human CD4; features and differences between the models were evaluated and discussed. Taken
together these results are of interest as MHC-II structure and function, molecular polymorphism and differential gene expression
are in correlation with disease resistance to virus and bacteria in teleost fish.
Additional information
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Citation
Buonocore, F. et al. 2007. Molecular cloning, differential expression and 3D structural analysis of the MHC class-II β chain from sea bass (Dicentrarchus labrax L.). "Fish and Shellfish Immunology" 23(4) 853-866
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Sponsor(s)
This work was supported by the European Commission within the project IMAQUANIM (EC contract number
FOOD-CT-2005-007103).
FOOD-CT-2005-007103).