The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. http://http://dspace.unitus.it:80 2013-05-25T23:32:55Z 2013-05-25T23:32:55Z Buonocore, Francesco Randelli, Elisa Casani, Daniela Guerra, Laura Picchietti, Simona Costantini, Susan Facchiano, Angelo M. Zou, Jun Secombes, Chris J. Scapigliati, Giuseppe http://hdl.handle.net/2067/1665 2011-06-27T20:38:24Z 2010-12-31T23:00:00Z

Title: A CD4 homologue in sea bass (Dicentrarchus labrax): Molecular characterization and structural analysis Authors: Buonocore, Francesco; Randelli, Elisa; Casani, Daniela; Guerra, Laura; Picchietti, Simona; Costantini, Susan; Facchiano, Angelo M.; Zou, Jun; Secombes, Chris J.; Scapigliati, Giuseppe Abstract: CD4 is a transmembrane glycoprotein fundamental for cell-mediated immunity. Its action as a T cell coreceptor increases the avidity of association between a T cell and an antigen-presenting cell by interacting with portions of the complex between MHC class II and TR molecules. In this paper we report the cDNA cloning, expression and structural analysis of a CD4 homologue from sea bass (Dicentrarchus labrax). The sea bass CD4 cDNA consists of 2071 bp that translates in one reading frame to give the entire molecule containing 480 amino acids. The analysis of the sequence shows the presence of four putative Ig-like domains and that some fundamental structural features, like a disulphide bond in domain D2 and the CXC signalling motif in the cytoplasmic tail, are conserved from sea bass to mammals. Real-time PCR analysis showed that very high levels of CD4 mRNA transcripts are present in thymus, followed by gut and gills. In vitro stimulation of head kidney leukocytes with LPS and PHA-L gave an increase of CD4 mRNA levels after 4 h and a decrease after 24 h. Homology modelling has been applied to create a 3D model of sea bass CD4 and to investigate its interaction with sea bass MHC-II. The analysis of the 3D complex between sea bass CD4 and sea bass MHC-II suggests that the absence of a disulfide bond in the CD4 D1 domain could make this molecule more flexible, inducing a different conformation and affecting the binding and the way of interaction between CD4 and MHC-II. Our results will add new insights into the sea bass T cell immune responses and will help in the identification of T cell subsets in teleost fishes to better understand the evolution of cell-mediated immunity from fish to mammals. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/

2010-12-31T23:00:00Z Casani, Daniela Randelli, Elisa Costantini, Susan Facchiano, Angelo M. Zou, Jun Martin, Sam Secombes, Chris J. Scapigliati, Giuseppe Buonocore, Francesco http://hdl.handle.net/2067/1680 2011-06-28T14:19:13Z 2008-12-31T23:00:00Z

Title: Molecular characterisation and structural analysis of an interferon homologue in sea bass (Dicentrarchus labrax L.) Authors: Casani, Daniela; Randelli, Elisa; Costantini, Susan; Facchiano, Angelo M.; Zou, Jun; Martin, Sam; Secombes, Chris J.; Scapigliati, Giuseppe; Buonocore, Francesco Abstract: The interferons (IFNs) are a large family of soluble cytokines involved in the immune response against viral pathogens. Three families of IFNs have been identified in mammals (type I, type II and type III) and, recently, homologues of type I and type II genes have been found in various teleost fish species. In this paper we report the cloning of a cDNA encoding an type I IFN molecule from sea bass (Dicentrarchus labrax L.), its expression analysis and gene structure and, finally, its 3D structure obtained by template-based modelling. The sea bass IFN cDNA consists of 1047 bp that translates in one reading frame to give the entire molecule containing 185 amino acids. The analysis of the sequence revealed the presence of a putative 22 amino acid signal peptide, two cysteine residues and three potential N-glycosylation sites. The sea bass IFN gene contains four introns as with other type I IFN teleost genes, except medaka that contains three introns. Real time PCR was performed after poly I:C stimulation of DLEC cell line to investigate the expression of sea bass IFN and Mx and an induction was observed for both genes. The predicted 3D structure of sea bass IFN is characterized by an “all-alpha” domain that shows an “up-down bundle” architecture made of six helices (ABB’CDE). The two cysteine residues present in the sequence (i.e. Cys23 and Cys126) are in a position and at a distance that suggest the possible formation of a disulfide bridge that may stabilize the structure. Our results will give the opportunity to investigate more in detail antiviral immune responses in sea bass and add to studies on the evolution of the IFN system in teleosts and Vertebrates more generally. Description: L'articolo è disponibile sul site dell'editore http://www.sciencedirect.com/

2008-12-31T23:00:00Z Buonocore, Francesco Randelli, Elisa Casani, Daniela Guerra, Laura Picchietti, Simona Costantini, Susan Facchiano, Angelo M. Zou, Jun Secombes, Chris J. Scapigliati, Giuseppe http://hdl.handle.net/2067/1565 2011-06-28T09:57:19Z 2007-12-31T23:00:00Z

Title: CD4 homologue in sea bass (Dicentrarchus labrax): molecular characterization and structural analysis Authors: Buonocore, Francesco; Randelli, Elisa; Casani, Daniela; Guerra, Laura; Picchietti, Simona; Costantini, Susan; Facchiano, Angelo M.; Zou, Jun; Secombes, Chris J.; Scapigliati, Giuseppe Abstract: CD4 is a transmembrane glycoprotein fundamental for cell-mediated immunity. Its action as a T cell coreceptor increases the avidity of association between a T cell and an antigen-presenting cell by interacting with portions of the complex between MHC class II and TR molecules. In this paper we report the cDNA cloning, expression and structural analysis of a CD4 homologue from sea bass (Dicentrarchus labrax). The sea bass CD4 cDNA consists of 2071 bp that translates in one reading frame to give the entire molecule containing 480 amino acids. The analysis of the sequence shows the presence of four putative Ig-like domains and that some fundamental structural features, like a disulphide bond in domain D2 and the CXC signalling motif in the cytoplasmic tail, are conserved from sea bass to mammals. Real-time PCR analysis showed that very high levels of CD4 mRNA transcripts are present in thymus, followed by gut and gills. In vitro stimulation of head kidney leukocytes with LPS and PHA-L gave an increase of CD4 mRNA levels after 4 h and a decrease after 24 h. Homology modelling has been applied to create a 3D model of sea bass CD4 and to investigate its interaction with sea bass MHC-II. The analysis of the 3D complex between sea bass CD4 and sea bass MHC-II suggests that the absence of a disulfide bond in the CD4 D1 domain could make this molecule more flexible, inducing a different conformation and affecting the binding and the way of interaction between CD4 and MHC-II. Our results will add new insights into the sea bass T cell immune responses and will help in the identification of T cell subsets in teleost fishes to better understand the evolution of cell-mediated immunity from fish to mammals. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/

2007-12-31T23:00:00Z