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研究発表を行った学会；
・第４０回日本発生生物学会・第５９回日本細胞生物学会　合同大会、2007年 5月28~30日(福岡)

タイトル；Identification of novel tyrosine kinase gene specifically expressed in Xenopus spermatogonial stem cell.

発表者；　宮本　健太朗　氏
　　　（熊本大学　大学院自然科学研究科　高宗研究室）
Abstract；
In Xenopus, primary spermatogonium (PG), a spermatogonial stem cell, is the largest cell (approximately 20 25m) in the testis and its size permits us to microinject foreign substances into it. Early-secondary spermatogonium (morphologically similar to PG) but not PG in the juvenile testis can undergo mitotic divisions with a concomitant decrease in its size and differentiate into the spermatogenic cells at later developmental stage such as late-secondary spermatogonia (LSG) under the cultivation condition. Thus, we can identify the PGs reliably in the dissociated cell population of the cultured juvenile testes by their cell size. In addition, the ability of the PG as a stem cell can be demonstrated by using the testis reconstruction system. Therefore, Xenopus becomes one of excellent laboratory animals for studying the intracellular molecular mechanisms controlling the decision between self-renewal and differentiation of spermatogonial stem cell.
In this study, we first isolated the PGs from cultured juvenile testes and constructed the cDNA mixture (PG-cDNA mixture). As the first attempt to find the molecules that are involved in controlling cell cycle of the PG, we amplified cDNAs encoding tyrosine kinase using degenerative primers devised by Wilks et al (1989). By comparing the cDNA clones with those obtained from LSG-cDNA mixture that had been constructed by the same method with the PG-cDNA mixture, we showed the presence of at least one cDNA encoding novel tyrosine kinase in the PG-cDNA mixture but not in the LSG-cDNA mixture.
Reference. Wilks AF, Kurban RR, Hovens CM, Ralph SJ, (1989). Gene, 85:67-74.