First description of programmed cell death10 (PDCD10) in rock bream (Oplegnathus fasciatus): Potential relations to the regulation of apoptosis by several pathogens

• The programmed cell death10 (RbPDCD10) cDNA was identified from a rock bream.
• RbPDCD10 was well-conserved six of the α-helix structure within the aligned sequence.
• RbPDCD10 gene was significantly expressed in the liver, RBC, gill and intestine.
• RbPDCD10 exhibited dramatic down-regulations following injections of Streptococcus iniae.

In this study, we isolated and characterized programmed cell death10 (PDCD10), which is known to be related to apoptosis, from rock bream (Oplegnathus fasciatus). The full-length rock bream PDCD10 (RbPDCD10) cDNA (1459 bp) contains an open reading frame of 633 bp that encodes 210 amino acids. Furthermore, multiple alignments revealed that the six of the α-helix bundles were well conserved among the other PDCD10 sequences tested. RbPDCD10 was significantly expressed in the liver, RBC (red blood cell), gill, intestine, trunk kidney and spleen. RbPDCD10 gene expression was also examined in several tissues, including the kidney, spleen, liver, and gill, under bacterial and viral challenges. Generally, all of the examined tissues from the fish that were infected with Edwardsiella tarda and the red sea bream iridovirus (RSIV) exhibited significant up-regulations of RbPDCD10 expression compared to the controls. However, RbPDCD10 expression exhibited dramatic down-regulations in all of the examined tissues following injections of Streptococcus iniae, which is major bacterial pathogen that is responsible for mass mortality in rock bream. Our results revealed that rock bream PDCD10 may be involved in the apoptotic regulation of rock bream immune responses.