title: Molecular and functional characterization of BAFF from the Yangtze alligator (Alligator sinensis, Alligatoridae).
abstract: B-cell activating factor (BAFF) from the TNF family is critical for B-cell survival and maturation. In this study, we identified a Yangtze alligator (Alligator sinensis, Alligatoridae) BAFF cDNA, designated as asBAFF, using reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The open reading frame of this cDNA encodes a 287-amino acid protein containing a predicted transmembrane domain and a furin protease cleavage site, similar to mammalian and avian BAFF. The amino acid identity between biologically soluble asBAFF (assBAFF) and csBAFF, hsBAFF, and msBAFF is 94, 76, and 71%, respectively. Real-time quantitative PCR analysis showed that the asBAFF gene is strongly expressed in the spleen. Since BAFF is always expressed as inclusion bodies in bacteria, it is difficult to purify. To enhance the soluble expression of assBAFF in Escherichia coli, we fused the extracellular region of the asBAFF gene to a small ubiquitin-related modifier gene (SUMO). Purified assBAFF was able to promote the survival of splenic lymphocytes and co-stimulate the proliferation of mouse B cells with anti-mouse IgM. These findings suggest that asBAFF plays an important role in the survival and proliferation of Yangtze alligator B cells, and because it is evolutionarily highly conserved, functional cross-reactivity exists between mammalian and Yangtze alligator BAFF.
authors.affiliation: Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing 210046, China; Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
authors.forename: Jia-Xin
authors.initials: JX
authors.lastname: Zhang
authors.affiliation: Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing 210046, China.
authors.forename: Ren
authors.initials: R
authors.lastname: Song
authors.affiliation: Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing 210046, China; Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Sang
authors.affiliation: Xuan Cheng Yangtze Alligator Breeding and Research Center of Anhui Province, Xuan Cheng 242000, China.
authors.forename: Si-Qing
authors.initials: SQ
authors.lastname: Sun
authors.affiliation: Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing 210046, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Ma
authors.affiliation: Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing 210046, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing 210046, China; Jiangsu Province Key Laboratory for Aquatic Crustacean Diseases, Life Sciences College, Nanjing Normal University, Nanjing 210046, China. Electronic address: zhangshuangquan@njnu.edu.cn.
authors.forename: Shuang-Quan
authors.initials: SQ
authors.lastname: Zhang
mesh_terms: D000489:Alligators and Crocodiles / Q000145:classification / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D053264:B-Cell Activating Factor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D049109:Cell Proliferation / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005786:Gene Expression Regulation; D008214:Lymphocytes / Q000166:cytology; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013154:Spleen / Q000166:cytology
chemical_list: D053264:B-Cell Activating Factor
keywords: B-cell survival; Real-time quantitative PCR; SUMO; Yangtze alligator BAFF; cDNA cloning