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Hirokazu Fujimoto1 , Ako Tokumasu1 , Rika Suzuki1 , Minesuke Yokoyama1
Mitsubishi Kasei Institute of Life Sciences, Machida, Japan 1
Hsc70t, a member of mouse Hsp70 family genes, encoding the spermatid-specific Hsp70 is transcribed in haploid germ cells and expressed under translational control during spermatogenesis. Analyses of genomic organization of the Hsc70t gene revealed that this gene is closely adjacent to the major heat-inducible Hsp70 gene (Hsp70.3) and that they are transcribed in head to head direction. This genomic organization was conserved in mouse, man and pig.
In this study, transgenic mice were produced to delimit the regulatory region required for developmental expression of the Hsc70t gene during mouse spermatogenesis. Results with multiple lines of transgenic mice containing Hsc70t promoter / luciferase reporter transgenes with varying lengths of Hsc70t genomic sequence showed that promoter sequences up to 134 bp upstream of the transcription start point and 69 bp downstream sequences are required for a testis specific expression of the transgene. Transgenic mice carrying deletion constructs of the promoter lacking under +9 bp downstream G-rich sequences showed testis-specific expression of the reporter gene, but not efficient. From developmental analyses of luciferase expression in juvenile testes of the transgenic mice, it has been shown that low efficiency of expression may be caused by instability of mRNA rather than inefficient transcription. Thus, regulatory sequences of the Hsc70t gene expression under transcriptional and translational levels were localized into a short region. Comparative genomic sequence analyses revealed that these sequences identified in the transgenic analyses were conserved among orthologous genes in mouse, man and pig.
This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.