Molecular cloning and characterisation of the rock bream, Oplegnathus fasciatus, Fas (CD95/APO-1), and its expression analysis in response to bacterial or viral infection

Fas belongs to the tumour necrosis factor (TNF) receptor superfamily and can transmit a death signal leading to apoptosis. In the present study, we isolated the full-length cDNA for rock bream (Oplegnathus fasciatus) Fas (RbFas). The full-length RbFas cDNA was 1770 bp long and contained an open reading frame of 957 bp that encoded 319 amino acid residues with a predicted molecular mass of 35.1 kDa. The 319 amino-acid predicted RbFas sequence is homologous to other Fas sequences, contains three cysteine-rich domains and a death domain (DD) and two potential N-glycosylation sites. Expression of RbFas mRNA was detected in nine different tissues from healthy rock bream and was the highest in red blood cells. In analyses of mitogen-stimulated RbFas expression in peripheral blood leucocytes, expression of RbFas mRNA was observed between 1 and 36 h after stimulation with LPS, and 1 and 3 h stimulation with poly I:C. In the case of bacterial injection, the RbFas transcript peaked 6 h after injection in both the kidney and the spleen. Otherwise, the RbFas transcript peaked after 1 h in spleen and 6 h in kidney following injection with RSIV.