Construction And Application Of PBC-rtTA Transgenic Mice Model

The tetracycline system is one of conventional transgenic technologies which is a reliable and effective tool for regulated transgene expression. The system can control the special expression of the transgene in special tissue or in special development period and also control the time and quantities of the expression,such as an effective "gene switch".ahead of the interest gene.rtTA is reverse tetracycline-controlled transactivator which fuction is just opposite to tTA.Tet-on system can control the expression of the transgene effectively.It is approved that SV40Tag has the characteristics to disrupt the control of host cell growth by interacting with cellular proteins and to induce tumorigenesis.SV40Tag is carcinogenic gene which SV40 is a basic virus substance inducing to cancer.In this research , we get rtTA form the vector Tet-on and then get the recombined gene pBC-rtTA with molecular biology method. It is so successful that we get five transgenic mice by microinjection into male nuclei. In this research, total 477 mice embryos were microinjected, 117 mice were born. The positive of micoinjection is high about 5%(5/117).To confirm the positive transgenic mice, southern blot was used to detect positive transgenic mice. The result showes five transgenic mice that is positive for gene pBC-rtTA. All F1 of these five founders have 50% positive rate after PCR detection, which is suggested that this is conformed to the laws of Mondel inheritance and transgene could be passaged to F1. The double positive transgenic progenies produced by mice transgenic for pBC-rtTA crossed to mice transgenic for TRE-SV40Tag which is belonged to our lab are induced by continuous doxycycline in water. Specially, the double positive transgenic progenies produced by mice transgenic for 31~#founder pBC-rtTA after 35d inducing ,we got RNA form heart brain kidney spleen lung liver and pancreas .It is suggested that the gene SV40Tag express in heart and brain by RT-PCR detection.The results of the research are suggested that it is successful to construst the transgenic mice pBC-rtTA which is a regulated element of tetracycline system and a tool mouse for our lab and also successful to construst the transgenic mice which are conditional expression of Simian Virus 40 T Antigen leading to regulatable development of tumor by tetracycline system. It is confirmed again that the tetracycline system is effective to regulate gene expression .