Testing transgenic regulatory elements through live mouse imaging

AbstractTo overcome positional and methylation effects on transgene expression, we developed a universal cloning cassette for in vivo assessment of regulatory elements using the luciferase reporter gene and the CCCD camera. Monitoring luciferase expression pattern in live mice enables screening of large numbers of transgenic founders quickly and inexpensively. We demonstrate that in the engineered transgenic mice, the chicken β-globin 5′HS4 insulator did not always provide the desirable expression pattern, and the Island Element, responsible for the demethylation of the surrounding DNA region, was not beneficial. Both tested liver-specific and developmentally regulated promoters exhibited the expected expression pattern in most transgenic founders

HCV Tumor Promoting Effect Is Dependent on Host Genetic Background

BACKGROUND: The hepatitis C virus (HCV) is one of the major risk factors for the development of hepatocellular carcinoma (HCC). Nevertheless, transgenic mice which express the whole HCV polyprotein (HCV-Tg) do not develop HCC. Whereas chronic HCV infection causes inflammation in patients, in HCV-Tg mice, the host immune reaction against viral proteins is lacking. We aimed to test the role of HCV proteins in HCC development on the background of chronic inflammation in vivo. METHODOLOGY/PRINCIPAL FINDINGS: We crossed HCV-Tg mice that do not develop HCC with the Mdr2-knockout (Mdr2-KO) mice which develop inflammation-associated HCC, to generate Mdr2-KO/HCV-Tg mice. We studied the effect of the HCV transgene on tumor incidence, hepatocyte mitosis and apoptosis, and investigated the potential contributing factors for the generated phenotype by gene expression and protein analyses. The Mdr2-KO/HCV-Tg females from the N2 generation of this breeding (having 75% of the FVB/N genome and 25% of the C57BL/6 genome) produced significantly larger tumors in comparison with Mdr2-KO mice. In parallel, the Mdr2-KO/HCV-Tg females had an enhanced inflammatory gene expression signature. However, in the N7 generation (having 99.2% of the FVB/N genome and 0.8% of the C57BL/6 genome) there was no difference in tumor development between Mdr2-KO/HCV-Tg and Mdr2-KO animals of both sexes. The HCV transgene was similarly expressed in the livers of Mdr2-KO/HCV-Tg females of both generations, as revealed by detection of the HCV transcript and the core protein. CONCLUSION: These findings suggest that the HCV transgene accelerated inflammation-associated hepatocarcinogenesis in a host genetic background-dependent manner

Multiple adaptive mechanisms to chronic liver disease revealed at early stages of liver carcinogenesis in the Mdr2-knockout mice Cancer Res 66

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