Cloning and Characterization of Oviduct Tubular Gland Cell Tissue-Specific Promoters of White Leghorn Chicken

摘要

Lactoferrin belongs to the transferrin family, the major function of which is in regulating the iron concentration in the blood stream and gastrointestinal tract. Lactoferrin has a remarkable antibacterial effect and plays an important role in the regulation of immune response. In a previous study, a full-length cDNA of 2133 bp from Macaca cyclopis lactoferrin gene (mLF) was cloned and sequenced. An effective promoter that can specifically drive the egg genes is necessary to establish a transgenic chicken line that can overexpress mLF in its eggs in addition to the viral promoters under development. Conalbumin and ovalbumin are the major proteins in egg white. The promoter regions of these two genes were cloned from the chromosomes of white Leghorn chicken in this study. This study uses fluorescence and luciferase assays to test the activities and tissue specificity of these two genes in primary cell cultures of white Leghorn chicken. The results show that the two promoters did not function in chicken muscle cells and fibroblast cells. However, the conalbumin promoter was active in chicken hepatocytes and oviduct tubular gland cells. By contrast, the ovalbumin promoter was active only in chicken primary oviduct tubular gland cells. Both promoters were regulated by a mixture of steroid hormones. The two promoters were also used to drive mLF expression in chicken primary hepatocytes and oviduct tubular gland cells. The results show that the ovalbumin and conalbumin promoters cloned in this study functioned in the chicken primary cell culture level. In the future, promoters will be further studied or reconstructed for gene transfer application in chicken.