Characterization of two thymosins as immune-related genes in common carp (Cyprinus carpio L.)

•Full cDNA sequences of two common carp thymosins have been identified.•The expression patterns of common carp thymosin genes in different tissues and during embryogenesis have been determined.•The transcriptional changes of carp thymosin genes after spring viraemia of carp virus (SVCV) infection have been detected.•The expressions of T lymphocyte-related genes increased after transient over-expression of carp thymosins in zebrafish. Prothymosin alpha (ProTα) and thymosin beta (Tβ) belong to thymosin family, which consists of a series of highly conserved peptides involved in stimulating immune responses. ProTα b and Tβ are still poorly studied in teleost. Here, the full-length cDNAs of ProTα b and Tβ-like (Tβ-l) were cloned and identified in common carp (Cyprinus carpio L.). The expressions of carp ProTα b and Tβ-l exhibited rise-fall pattern and then trended to be stable during early development. After spring viraemia of carp virus (SVCV) infection, the carp ProTα b and Tβ-l transcripts were significantly up-regulated in some immune-related organs. When transiently over-expressed carp ProTα b and Tβ-l in zebrafish, these two proteins up-regulated the expressions of T lymphocytes-related genes (Rag 1, TCR-γ, CD4 and CD8α). These results suggest that carp ProTα b and Tβ may ultimately enhance the immune response during viral infection and modulate the development of T lymphocytes in teleost.