Characterization and expression analysis of sox3 in medaka gonads

Abstract

Numerous studies have showed that sox3 is involved in neurogenesis and sex differentiation in vertebrates. However, the accurate expression pattern is still unclear in fish. In this study, medaka sox3 was isolated and its expression patterns were compared with germ cell gene vasa in adult gonads. By reverse transcription-polymerase chain reaction (RT-PCR) analysis, sox3 RNA expression was detected in the brain, eyes and gonads. By chromogenic and fluorescent in situ hybridization, sox3 was present in the oogonia and early stages of oocytes as well as granulosa cells and theca cells in the later stages; in the testis, sox3 was occurred in the Sertoli cells and sperm with a specific signal in the location of chromatid body of sperm; in the embryos, sox3 was expressed in the central nervous. These results suggest that medaka sox3 gene was occurred in somatic and germ cells in adult gonads of both sexes, involved in the process of spermatogenesis, as well as the development of the nervous system. This study provides a precise expression pattern of sox3 and suggests that sox3 may be involved in gonadal and nervous system development of fish.