| Research Abstract |
Application of Cre-loxP system for gene engineering in mice.
To develop the technology required for tissue and stage restricted gene disruption in mice, we tried the application of Cre-loxP system and obtained following results. At first, we constructed the gene targeting vector which had three loxP sequences at just 5' and 3' ends of Neo-TK cassette (inserted at upstream of the target sequence) and at downstream of the target sequence. Then, homologous recombinant ES cells were isolated and the Neo-TK cassette was removed off by the expression of Cre-recombinase. These recombinant ES cells were injected into fertilized eggs to generate chimeric mice. The histological and functional analyzes of hetero and homozygous mutant mice are now in progress.
2) Isolation and analysis of premature aging mice.
We recently developed a unique short life mouse strain in which a single gene mutation caused a premature aging, including arteriosclerosis, osteoporosis, impaired spermatogenesis and oocyte maturation, soft tissue calcification, atrophy of thymus, pulmonary emphysema, degeneration of Purkinje cells, and impaired glucose metabolism.However, the mice did not show any abnormality in lipid metabolisms. We have isolated the causative gene from both mouse and human. Furthermore, the ectopic expression of the isolated gene successively rescued the mutant phenotypes. The gene has been found to be a novel one encoding a membrane protein and expressed mainly in kidney and brain. In human a secreted protein, in adition to membrane protein, is generated from same gene by alternative splicing mechanism.
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