2006 Fiscal Year Final Research Report Summary
Elucidation of induction mechanism of imposex in prosobranch gastropods
| Project/Area Number |
17380121
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General fisheries
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| Research Institution | National Institute for Environmental Studies |
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Principal Investigator |
HORIGUCHI Toshihiro National Institute for Environmental Studies, Research Center for Environmental Risk, Special Senior Researcher, 環境リスク研究センター, 主席研究員 (30260186)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAISHI Hiroaki National Institute for Environmental Studies, Research Center for Environmental Risk, Director, 環境リスク研究センター, センター長 (10124348)
OHTA Yasuhiko Tottori University, Faculty of Agriculture, Professor, 農学部, 教授 (60069078)
NISHIKAWA Tomohiro National Institute for Environmental Studies, Research Center for Environmental Risk, Assistant Staff, 環境リスク研究センター, 契約職員 (10391137)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Imposex / Penis / Vas deferens / Cell differentiation / Cell proliferation / Retinoid X receptor(RXR) / Tributyltin(TBT) / Triphenyltin(TPT) |
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| Research Abstract |
The developmental process of penis and vas deferens was histologically examined in the imposex-exhibiting female rock shell (Thais clavigera). In the chain of the study to clarify the roles of retinoid X receptor (RXR) on the development of imposex caused by organotin compounds in gastropods, the RXR gene expression in various tissues (ctenidium, testis or ovary, digestive gland, penis or penis forming area and ganglia) of male, female and imposex-exhibiting female rock shells was analyzed using the real time RT-PCR method. The highest value of RXR gene expression was observed in penis among all of tissues analyzed in both males and imposex-exhibiting females, meanwhile slightly/insignificant higher value was observed in penis forming area among all of tissues of normal females. The RXR gene expression in penis of males and imposex-exhibiting females was 9.3 and 6.2 times higher than that in the penis forming area of normal females, respectively (p<0.05 and p<0.01, respectively). These results suggest that RXR plays an important role for differentiation and growth of penis (possibly, as well as vas deferens) in both males and females exposed to organotin compounds, such as tributyltin (TBT). Results on immunohistochemical staining of T clavigera tissues against anti-RXR antibody and anti-PCNA antibody suggested that RXR could be responsible for inducing cell proliferation. Expression of RXR protein was also observed in Thais bronni, a close species to T. clavigera, based on results on immunohistochemical staining for anti-RXR antibody. Temporal change of both RXR gene and protein expression is observed with T. clavigera exposed to organotin compounds in a flow-through exposure system. Target genes of RXR as well as genes induced by exposure to organotins have been tried to clone from Tclavigera tissues, and some preliminary results on cloning the genes have been obtained.
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Research Products
(11 results)
