Zheng-Bing Guan

Construction and characterization of two versions of bifunctional EGFP–sTRAIL fusion proteins

The extracellular portion (amino acids 95–281 or 114–281) of the human tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) was genetically linked to the C terminus of the fluoresce-enhanced green fluorescent protein variant (EGFP) to generate two versions of EGFP–sTRAIL fusion proteins, designated EGFP–sTR95 and EGFP–sTR114, respectively. The two versions of EGFP–sTRAIL fusion proteins both induce extensive apoptosis in lymphoid as well as nonlymphoid tumor cell lines. In addition, the two versions of fusion proteins retain similar fluorescence spectra to those of EGFP and have shown the specific binding to TRAIL receptor-positive cells; thus, the stained cells could be analyzed with flow cytometry. Hence, the two versions of fusion proteins represent a readily obtainable source of biologically active sTRAIL that may prove useful in exploit fully the characteristics of both the soluble TRAIL and its receptor system.

Molecular characterization of cytokine TWEAK and its receptor Fn14 in pig (Sus scrofa)

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is a member of the tumor necrosis factor superfamily (TNFSF). The interaction of TWEAK with its receptor fibroblast growth factor-inducible 14 (Fn14) regulates multiple cellular responses, including stimulation of proliferation, migration, apoptosis, angiogenesis, and induction of proinflammatory cytokines. This paper reports for the first time the molecular cloning of porcine TWEAK and Fn14 by EST and RACE strategies. The full-length cDNA of porcine TWEAK is 1327bp, including an open reading frame (ORF) of 747bp. Its genomic DNA consists of seven exons and six introns and is approximately 10kb in size by computer-assisted analysis. Sequence similarity at the amino acid level between porcine TWEAK and human or mouse was 95 and 92%, respectively. The full-length cDNA of porcine Fn14 contains 691bp, of which 390bp are the ORF. Sequence similarity at the amino acid level between porcine Fn14 and human, or mouse, or frog was 95, 93 and 64%, respectively. Real-time quantitative PCR (Q-PCR) analysis revealed that both TWEAK and Fn14 are constitutively expressed in various tissues in pig. Our results suggest that the TWEAK-Fn14 pathway is evolutionarily highly conserved. It will be helpful for investigation on the biological role of the TWEAK/Fn14 system in this important animal model. Furthermore, it provides insight into the molecular evolution of the emerging TWEAK and Fn14 families.