Research on exogenous gene function in cultured cell line cells is guaranteed by two biological processes, efficient gene transduction and errorless gene expression. Fish cells are not easy for exogenous gene transduction and expression depending on the gene delivery method used and the transgene promoter. CPPs), such as the CPP of the human immunodeficiency virus type 1 TAT protein, poly-arginine (6–12 residues), and the CPP derived from flock house virus (FHV), peptides, proteins, and oligonucleotides into mammalian cells to modulate biological activities inside cellsAlthough it has been shown that CPPs can mediate efficient delivery into a wide variety of mammalian cell types, the transduction of proteins to cultured fish cells is considered more challenging. rupies in the form of recombinant proteins by introducing spermary cell line cells in vitro. Cells treated with proteins below 8 μg/mL induced no or minor toxic effects while higher concentrations gave rise to cytotoxicity. The transduction efficiency of the recombinant protein with 6 His tag, evaluated by western blotting using an anti-His antibody, reached a maximum level at 8 μg/mL and in a dose responsive fashion. Based upon the optimal concentration of proteins for transduction, Sox2-11R-H6 in TRS cells was further imaged using a fluorescence microscope. The recombinant protein Sox2-11R-H6was detected in the cytoplasm and even in the nucleus. Taken together, the value of the 11R translocation domain in facilitating the routing of proteins to the cytosol of cultured fish cells was confirmed. However, whether the functionality of the transcription factor was disturbed by addition of this domain in the construct needs further exploration. The subcellular localization of transduced proteins may depend on the nature of imported proteins, the cell type, and delivery approach. As a transcription factor, must contain a nuclear localization signal (NLS) so that it can be transported to the nucleus to bind to its target octamer motif and transactivate its target genes. Our observation that fluorescence intensity was higher in the nucleus than cytoplasm, indicates that the exogenous protein Sox2 enters the fish nucleus. Further experiments are needed to decide whether nuclear location ofSox2-11R-H6 was facilitated by a nuclear localization signal or the cell penetrating peptide.