Hepatitis B virus ( HBV) is an important pathogen threatening to human health. Up to date, various of cell infection models and animal models for HBV and the host are widely used in the exploring research of infection mechanism, new drug development and effective therapeutic method for HBV. However, these models have some defects, such as low infection rate, rather short infective stage, and comparatively large species differences with human, and so on. Among them, the biggest problem is that these models cannot completely simulate HBV infection process and pathological changes naturally occurred in human. Herein, the major HBV infection models developed in the past fifteen years, as well as the latest research progress, are presented as a brief review, to provide a reference for constructing novel HBV infection models in the future.

The aim of this study was to screen the active regions and transcription factor binding sites in the promoter of the CBD103 gene related to Arctic fox coat color, and to provide a basis for revealing the molecular genetic mechanism of CBD103 gene regulating the coat color formation. The 5'-flanking region fragment 2 123 bp of Arctic fox CBD103 gene was cloned, and 4 truncated promoter reporter vectors of different lengths were constructed. The promoter activity was detected by the dual-luciferase reporter assay system. Point mutations were performed on the 3 predicted specificity protein 1 (Sp1) transcription factor binding sites in the highest promoter active region, and 3 mutant vectors were constructed. The activity was then detected by the dual-luciferase reporter assay system. The results showed that the region 1 656 (-1 604/+51) had the highest activity in the 4 truncated promoters of different lengths, and the promoter activity of the three mutant vectors constructed in this region were significantly lower than that of the wild type (fragment 1 656). The region of -1 604 /+51 was the core promoter region of CBD103 gene in Arctic fox and -1 552/-1 564, -1 439/-1 454 and -329/-339 regions were positive regulatory regions. This study successfully obtained the core promoter region and positive regulation regions of the Arctic fox CBD103 gene, which laid a foundation for further study on the molecular genetic mechanism of this gene regulating Arctic fox coat color.
Animals ; Binding Sites ; Foxes ; Luciferases ; Promoter Regions, Genetic ; Sp1 Transcription Factor ; beta-Defensins