An embryo-based genotyping enables prenatal diagnosis of genes or markers for economically important traits or genetic disorders, and establishment of an embryo-based genotyping system is hoped to contribute efficiently selecting bulls as sires. We performed the embryo-based genotyping for CL-16 and SREBP-1 that are causative gene for CL-16 deficiency and fatty acid composition-related gene, respectively. In-vitro embryos were produced from Ovum Pick Up (OPU). Cells detachment was performed on 5 days after an in-vitro fertilization. To create nuclear transplant embryos for progeny(clone)test, these detached cells were used as a donor. We carried out genetic screening using developmental arrest embryos on 5-6 days after the nuclear transplant. The genotypes for CL-16 and SREBP-1 were successfully determined with the nuclear transplant embryo, and the genotypes determined by postnatal test were same as one by prenatal test. It was suggested that we will be able to get prenatally genotypic information of the candidate sire, and select effectively the sires harboring genotypes associated with the traits of interest.

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Tmem48 encodes a nuclear membrane protein comprising the nuclear pore complex and a mutation in this gene is responsible for the gametogenesis defects and skeletal malformations in the sks mutant mice. Since a nucleotide substitution in the Tmem48 gene results in arrest of meiosis that causes defective spermatogenesis in the sks mice, the function of nuclear pore complex thorough TMEM48 is suggested to be essential for mammalian gametogenesis. In the present study, therefore, we attempted to identify proteins that have potentially important functions in mammalian gametogenesis by screening of the testis expressing proteins that bind to TMEM48 using yeast two-hybrid method. As a result of the screening, we identified total of 31 proteins which are suggested to interact with TMEM48. The expression analysis of these genes in various mouse tissues indicated specific expressions of Dynll2, Pabpc2, Spink2, Txnl4b genes in the testis. Then, we examined expressions of these genes during the first wave of spermatogenesis at new born stages, in which synchronized spermatogenesis is observed in all seminiferous tubules, and found that these genes express at specific stages of meiosis during spermatogenesis. These findings suggested that the proteins encoded by these genes play essential roles in mammalian gametogenesis.

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