TY - JOUR
T1 - Planarian D-amino acid oxidase is involved in ovarian development during sexual induction
AU - Maezawa, Takanobu
AU - Tanaka, Hiroyuki
AU - Nakagawa, Haruka
AU - Ono, Mizuki
AU - Aoki, Manabu
AU - Matsumoto, Midori
AU - Ishida, Tetsuo
AU - Horiike, Kihachiro
AU - Kobayashi, Kazuya
N1 - Funding Information:
We are grateful to Dr. P. A. Newmark (University of Illinois) for generously providing the L4440 vector used in our RNAi analysis, and Dr. Yuni Nakauchi and Mr. Ryo Sasaki (Yamagata University) for their invaluable assistance collecting B. brunnea. We also thank the members of our laboratory for their valuable comments. This work was supported in part by a Grant-in-Aid for Scientific Research in Innovative Areas (“Regulatory Mechanism of Gamete Stem Cells; K.K., # 20116007 ), a Grant-in-Aid for Scientific Research (B) (K.K., # 22370026 ), a Grant-in-Aid for Scientific Research (C) (T.M., # 22603010 ), a Grant-in-Aid for Scientific Research (C) (H.T., #24590351), The NAITO Foundation, and a Grant-in-Aid for the Global Centers of Excellence (GCOE) Program (2007–2012 to Keio University) from the Ministry of Education, Culture, Sports, Science and Technology, Japan .
PY - 2014/5
Y1 - 2014/5
N2 - To elucidate the molecular mechanisms underlying switching from asexual to sexual reproduction, namely sexual induction, we developed an assay system for sexual induction in the hermaphroditic planarian species Dugesia ryukyuensis. Ovarian development is the initial and essential step in sexual induction, and it is followed by the formation of other reproductive organs, including the testes. Here, we report a function of a planarian d-amino acid oxidase, Dr-DAO, in the control of ovarian development in planarians. Asexual worms showed significantly more widespread expression of Dr-DAO in the parenchymal space than did sexual worms. Inhibition of Dr-DAO by RNAi caused the formation of immature ovaries. In addition, we found that feeding asexual worms 5 specific d-amino acids could induce the formation of immature ovaries that are similar to those observed in Dr-DAO knockdown worms, suggesting that Dr-DAO inhibits the formation of immature ovaries by degrading these d-amino acids. Following sexual induction, Dr-DAO expression was observed in the ovaries. The knockdown of Dr-DAO during sexual induction delayed the maturation of the other reproductive organs, as well as ovary. These findings suggest that Dr-DAO acts to promote ovarian maturation and that complete sexual induction depends on the production of mature ovaries. We propose that Dr-DAO produced in somatic cells prevents the onset of sexual induction in the asexual state, and then after sexual induction, the female germ cells specifically produce Dr-DAO to induce full maturation. Therefore, Dr-DAO produced in somatic and female germline cells may play different roles in sexual induction.
AB - To elucidate the molecular mechanisms underlying switching from asexual to sexual reproduction, namely sexual induction, we developed an assay system for sexual induction in the hermaphroditic planarian species Dugesia ryukyuensis. Ovarian development is the initial and essential step in sexual induction, and it is followed by the formation of other reproductive organs, including the testes. Here, we report a function of a planarian d-amino acid oxidase, Dr-DAO, in the control of ovarian development in planarians. Asexual worms showed significantly more widespread expression of Dr-DAO in the parenchymal space than did sexual worms. Inhibition of Dr-DAO by RNAi caused the formation of immature ovaries. In addition, we found that feeding asexual worms 5 specific d-amino acids could induce the formation of immature ovaries that are similar to those observed in Dr-DAO knockdown worms, suggesting that Dr-DAO inhibits the formation of immature ovaries by degrading these d-amino acids. Following sexual induction, Dr-DAO expression was observed in the ovaries. The knockdown of Dr-DAO during sexual induction delayed the maturation of the other reproductive organs, as well as ovary. These findings suggest that Dr-DAO acts to promote ovarian maturation and that complete sexual induction depends on the production of mature ovaries. We propose that Dr-DAO produced in somatic cells prevents the onset of sexual induction in the asexual state, and then after sexual induction, the female germ cells specifically produce Dr-DAO to induce full maturation. Therefore, Dr-DAO produced in somatic and female germline cells may play different roles in sexual induction.
KW - D-Amino acid oxidase (DAO)
KW - D-Amino acids
KW - Dugesia ryukyuensis
KW - Ovarian development
KW - Planarian
KW - Sexual induction
UR - http://www.scopus.com/inward/record.url?scp=84897028615&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84897028615&partnerID=8YFLogxK
U2 - 10.1016/j.mod.2013.12.003
DO - 10.1016/j.mod.2013.12.003
M3 - Article
C2 - 24434168
AN - SCOPUS:84897028615
SN - 2667-291X
VL - 132
SP - 69
EP - 78
JO - Cells and Development
JF - Cells and Development
IS - 1
ER -