Analysis and Expression of Tumor Necrosis Factor Receptor Homolog from LCDV-C

Tumor necrosis factor receptor (TNFR) plays an important role in the evasion of immune response by large DNA viruses. TNFR is a homologue of cellular receptors. Lymphocystis disease virus, an iriduvirus, isolated in China (LCDV-C) is a large DNA virus. Primers were designed based on conserved TNFR nucleotide sequences in iridoviruses and used to amplify the homologue in LCDV-C. A DNA fragment of 834 bp was generated and sequenced. The recombi-nant prokaryotic expression plasmid containing this fragment was constructed and expressed in E. coli. DE3. An expected 45kDa fusion protein was isolated by SDS-PAGE. Computer analysis indicated that LCDV-C TNFR homologue encodes a 278aa putative protein, which contains a typical cysteine-rich domain. It shares 34% identity with flounder TNFRII.