THE ORIGIN OF TESTICULAR SOMATIC CELLS IN THE GONAD DURING SEX CHANGE IN THE PROTOGYNOUS WRASSE, HALICHOERES TRIMACULATUS
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1
University of the Ryukyus, Graduate School of Engineering and Science, Japan
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2
University of the Ryukyus, Tropical Biosphere Research Center, Japan
The three-spot wrasse (Halichoeres trimaculatus) changes sex from female to male. Oocytes in the ovary disappear completely, and male germ cells and somatic cells comprising testicular tissue arise anew during the process of sex change. In general, the differentiation of germ cells is controlled by somatic cells that surround the germ cells. Thus, we believe that it is essential to understand how testicular somatic cells differentiate during sex change. Therefore, the purpose of this study was to identify the origin of testicular somatic cells in the gonads by analyzing cellular behavior during sex change. Apoptosis in the sex changing gonad was analyzed by immunodetection of Caspase-3 which is one of the key mediators of apoptosis. However, few Caspase-3 immunoreactive somatic cells were found to be present during sex change, which suggests that ovarian somatic cells survive during the regression of ovarian tissue. Cell proliferation was investigated by 5-bromodeoxyuridin (BrdU) uptake in sex changing gonads. Interestingly, BrdU immunoreactivity (BrdU-ir) was detected in many granulosa cells surrounding the degenerating oocytes at an early stage of sex change. In addition, BrdU-ir was also detected in a few epithelial cells covering ovigerous lamella and somatic cells associated with gonial germ cells. To define the fate of proliferating cells, BrdU pulse chase analysis was performed. At an early stage, BrdU immunoreactive somatic cells were of three types, granulosa cells, epithelial cells and somatic cells associated with gonial germ cells. In spermatogenic gonads at 2 weeks after BrdU injection, BrdU-ir was detected in the somatic cells in the central region of the lamella, Sertoli cells surrounding the cyst of spermatogenic germ cells, and somatic cells associated with gonial germ cells. These results suggest that some testicular somatic cells originate from functional somatic cells of the ovary.
Acknowledgements
This study was supported by a Grant-in-Aid for Science Research from the Ministry of Education, Science, Sports and Culture of Japan and SORST, JST
Keywords:
Apoptosis,
Cell Proliferation,
Gonad,
protogyny,
sex change,
three-spot wrasse
Conference:
NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology, Ann Arbor, United States, 13 Jul - 16 Jul, 2011.
Presentation Type:
Poster
Topic:
Sex determination and differentiation
Citation:
Nozu
R,
Horiguchi
R,
Murata
R,
Kobayashi
Y and
Nakamura
M
(2011). THE ORIGIN OF TESTICULAR SOMATIC CELLS IN THE GONAD DURING SEX CHANGE IN THE PROTOGYNOUS WRASSE, HALICHOERES TRIMACULATUS.
Front. Endocrinol.
Conference Abstract:
NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology.
doi: 10.3389/conf.fendo.2011.04.00038
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Received:
14 Jul 2011;
Published Online:
09 Aug 2011.
*
Correspondence:
Mr. Ryo Nozu, University of the Ryukyus, Graduate School of Engineering and Science, Motobu, Okinawa, Japan, with_football@yahoo.co.jp