Transgenic medaka enables easy oocytes detection in live fish.
Easy oocyte detection in living specimens benefits various developmental biology and environmental toxicology studies. One of the earliest markers of sex differentiation in medaka (Oryzias latipes) is oocyte development. Within the field of toxicology, a simple detection method for induced oocyte in the testis (testis-ova) as a result of endocrine disruption is necessary. In this study we produced transgenic medaka whose oocytes were labeled with fluorescent proteins using the regulatory region of the 42Sp50 gene, an isoform of polypeptide elongation 1-alpha. Short (201 nt) 5'- and 3'-flanking regions were sufficient for reporter gene expression. GFP expression was first observed in female germ cells approximately 5 days post-hatching. In the mature ovaries, germ cells showed such intense fluorescence that the fluorescence was observed from outside the body wall. In contrast, very faint fluorescence was observed in the mature testes. Testis-ova, oocytes artificially induced in the testes, were also labeled with GFP. These findings indicate through the use of transgenic medaka, that detection of female germ cells was straightforward and this transgenic medaka model proves useful for tracking female germ cells in developmental and toxicological studies.
Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan. kinoshit@kais.kyoto-u.ac.jp
Masato
M
Kinoshita
Gensei
G
Okamoto
Takashi
T
Hirata
Ai
A
Shinomiya
Tohru
T
Kobayashi
Yuko
Y
Kubo
Hiroshi
H
Hori
Akira
A
Kanamori
D000818:Animals; D030801:Animals, Genetically Modified / Q000196:embryology* / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006066:Gonads / Q000166:cytology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008297:Male; D008856:Microscopy, Fluorescence; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D009990:Oryzias / Q000196:embryology* / Q000235:genetics; D020648:Peptide Elongation Factor 1 / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019849:Sex Determination Processes
D017931:DNA Primers; D020648:Peptide Elongation Factor 1; D049452:Green Fluorescent Proteins