Article ID Journal Published Year Pages File Type
2432858 Fish & Shellfish Immunology 2010 8 Pages PDF
Abstract

B-cell activating factor (BAFF), belonging to the TNF family, is a critical cytokine for B-cell survival, proliferation, maturation and differentiation. In the present study we cloned the cDNA of zebrafish (Danio rerio) BAFF (designated zBAFF) by reverse transcription-PCR (RT-PCR). The open reading frame (ORF) of zBAFF consists of 807 bases encoding a protein of 268 amino acids. The deduced amino acid sequence of its cDNA possessed the TNF family signature, a transmembrane domain, and three cysteine residues, which are the typical characteristics of TNF gene in mammals and birds. Phylogenetic analysis exhibits the highest identity score 67.6, 61.4 and 66.9% with the rainbow trout, tetraodon and salmon counterparts, respectively. The identity to avian and mammalian BAFFs ranges from 49.7 to 53.8%. Recombinant soluble zBAFF (zsBAFF) was fused with a small ubiquitin-related modifier gene (SUMO) to enhance the soluble expression level in Escherichia coli BL21 (DE3). The resulting fused protein SUMO-zsBAFF was highly expressed in BL21 (DE3) with a molecular weight of 38 kDa. The fusing protein was purified using metal chellate affinity chromatography (Ni-NTA) and cleaved by a SUMO-specific protease, then confirmed by SDS-PAGE and Western blotting analysis. In vitro, the MTT assay indicated that the purified zsBAFF as well as SUMO-zsBAFF proteins were able to promote spleen lymphocyte survival in a dose-dependent manner also to co-stimulate the proliferation of mammalian B-cells with anti-IgM. Thus, the fusion protein represents a readily obtainable source of biologically active zsBAFF that may prove useful in further studies on zebrafish BAFF and its receptors.

Related Topics
Life Sciences Agricultural and Biological Sciences Aquatic Science
Authors
, , , , ,