Search

Abstract: Interferon-γ-inducible-lysosomal thiol reductase (GILT) plays a key role in the processing and presentation of MHC class II-restricted antigen (Ag) by catalyzing disulfide bond reduction, thus unfolding native protein Ag and facilitating subsequent cleavage by proteases. In this study, we reported the cloning of a GILT gene homologue from chicken (designated cGILT). The open reading frame (ORF) of cGILT consists of 762 bases, encoding a protein of 253 amino acids, with a putative molecular weight of 28kDa. The deduced protein possesses the typical structural feature of known GILT proteins, including an active-site motif, a GILT signature sequence, and 6 conserved cysteines. Genomic analysis revealed that cGILT gene, spanning a 1868bp fragment, contained seven exons interrupted by six introns. The result of real-time PCR showed that cGILT mRNA was expressed in a tissue-specific manner, while the cGILT mRNA expression was obviously up-regulated in spleen and PBMCs after stimulation with lipopolysaccharide (LPS). After expression as a soluble protein in Escherichia coli and purification by Ni-NTA affinity chromatography, cGILT was demonstrated to exhibit thiol reductase activity on IgG substrate. [Copyright &y& Elsevier]

Abstract: B cell activating factor (BAFF), belonging to the tumor necrosis factor (TNF) family, plays an important role in B cell survival, proliferation and differentiation. In the present study, we amplified the cDNA of dog (Canis familiaris) BAFF (designated doBAFF) from spleen by reverse transcription-PCR (RT-PCR) and rapid amplification of cDNA ends (RACE) strategies. The open reading frame (ORF) of doBAFF covers 879bp encoding 292 amino acids, with a 152-aa mature peptide. The soluble mature part of doBAFF (dosBAFF) shares 91.5%, 72.1%, 96.7%, 94.0% and 91.5% identity with the human, mouse, cattle, pig and rabbit counterparts, respectively. The predicted three-dimensional (3D) structural analysis of dosBAFF analyzed by “comparative protein modeling” revealed that it was very similar to its human counterpart. Real-time quantitative PCR analysis revealed that doBAFF was mainly expressed in spleen. Two fusion proteins SUMO-dosBAFF and GFP/dosBAFF were efficiently expressed in Escherichia coli BL21 (DE3) and purified using metal chelate affinity chromatography (Ni-NTA). Laser scanning confocal microscopy analysis showed that GFP/dosBAFF could bind to the mouse splenic B-cell. In vitro, SUMO-dosBAFF and GFP/dosBAFF were able to promote the survival/proliferation of dog lymphocytes or mouse splenic B cells with/without anti-IgM. Therefore, BAFF may be a potential immunologic factor for enhancing immunological efficacy in dog. [Copyright &y& Elsevier]