| Tiki gene is a new gene that is found by Xi He's research team in Children's Hospital of Harvard University .Based on their studies in frog, they identified the Tiki1 and Tiki2 as Wnt inhibitors and they have confirmed that human Tiki1 and Tiki2 act in a similar manner. Their characterization of Tiki1 in the frog indicates that is critical for head induction, similar to role of another Wnt inhibitor Dkk1 (Dkk1 loss of function frog and mouse fail to develop anterior head structres). Both Tiki1 and Tiki2 are found in most vertebrates, while Tiki1 misses in rodents including mice and rats.However Tiki1 may still be critical for early (non-rodent) mammal head development and may be clinically important for human embryogenesis. Since function Tiki1 studies are not able to be conducted in the mouse, a classic model for exploring a novel gene in mammalian animals, the pig will serve as an excellent model organism to generate a mammalian Tiki1 knockout to model human Tiki1 disease. Our research focus on the expression of Tiki gene during porcine embryogenesis and in adult organs.We used PCR to detect expression of Tiki gene in adult porcine organs and our data show that Tiki1 gene is expressed in porcine liver, lung,mammary gland and ovary while Tiki2 gene is expressed in heart. The sequencing results of partial Tiki gene obtained from above organs are highly homologous(80%) in different species,indicating that this gene may have important functions.Whole-mount in situ hybridization during Day12-15 (pre-streak to neural groove) porcine embryo indicate that pig Tiki1 is located in the anterior embryo.These corresponding results have a good agreement with the Tiki1 WISH data on frog,implying that pig Tiki1 may play a critical role in head induction.While Tiki2 is expressed along the axis,which is accordant with WISH results on the mouse. Furthermore, we successfully constructed pig Tiki1 targeting vector in order to study function of Tiki1 during pig embryogenesis . |
PDF Full Text Request