Expression profile of cytokine and transcription factor genes during embryonic development of zebrafish Danio rerio

Cytokines are a group of proteins that are involved in a variety of immunological and inflammatory reactions. Recently, it has been reported that cytokine genes also play an important role during development in mammals. In fish, however, little is known about the role of immune-related genes during embryogenesis. Here, we report the mRNA expression of some cytokines and transcription factors during embryonic development in zebrafish. In reverse transcriptase polymerase chain reaction (RT-PCR) analysis, the expression of il1b, tnfb, ifn1, il12ba, eomesa and eomesb genes were detected before the development of the immune system in zebrafish embryos. Genes il1b, tnfb and eomesb showed high level expression at the specific stages, while eomesa was highly expressed at all the stages examined. Moreover, the difference in expression pattern was observed between two isoforms of tnf and eomes genes. These results suggest that immune genes expressed at early embryonic stages are not involved in immunity but development, and two isoforms have different functions not only in adulthood but also during embryonic development.