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(739) CLONING AND CHARACTERIZATION OF TESTIS SPECIFIC GTPase. Chattopadhyay, Soma1, Seo, Ji Ho1, Seo, Yu Mi1, Lee, Keesook1, 1 Hormone Research Center, School of Biological Sciences and Technology, Gwangju, Republic of Korea ABSTRACT- In the course of cloning genes that are induced by androgen in murine testis, we identified a gene, testis specific GTPase (TSG), which is expressed in a testis-specific manner. Full length cDNA was isolated and its sequence analysis revealed an open reading frame of 1593 base pairs, encoding a protein of 530 amino acids. Sequence alignment of the cDNA with mouse genomic sequence revealed that this gene is located on chromosome 4 and consists of 16 exons. Northern blot analysis showed that TSG was expressed only in the testis and its message was first detected at around 24 days postpartum and down regulated thereafter to adulthood. In-situ hybridization analysis of the testis showed that TSG is mainly expressed in seminiferous tubules. A leucine zipper motif and a bipartite nuclear targeting sequence are located in the amino terminal region. Carboxy terminal part of TSG protein contains several domains which are characteristic of small GTPases such as Rab, Ras, Ran and ARF. ATP/GTP binding site motif A(P- loop) is one of the characteristic domains. The preliminary data from GTP overlay experiments with bacterially expressed TSG protein revealed that TSG binds to GTP. These data suggest that TSG, being expressed in a testis- and development stage- specific manner, may have a role in male germ cell development. KEY WORDS: Testis , Androgen, GTPase |
