Effect of human factor Ⅸ intron 1 inserted in forward orientation into retroviral vectors on expression of factor Ⅸ in muscle cells / 第二军医大学学报

ABSTRACT

Objective:To investigate the effects of human factor Ⅸ (FⅨ) intron 1 inserted in forward orientation into retroviral vector on the expression of FⅨ in muscle cells. Methods: Two FⅨ mini-genes, FⅨm1 and FⅨm2, were inserted in forward orientation into retroviral vector backbone, LⅨSN, constructing 2 vectors named LⅨm1SN and LⅨm2SN, containing shortened intron of 1.4 and 0.3 kb, respectively. Retrovirus was made by transfecting PA317 packaging cells. Transient and stable expression of FⅨ was tested in SCID mouse muscle cells (SCID-MB). Results: The vector titers and expression levels of LⅨm1SN and LⅨm2SN in SCID-MB were 1 to 2 folds higher than that of LⅨSN. Some SCID-MB colonies transfected with LⅨm2SN contained intact FⅨm2 inton elements, suggesting that splicing of virus mRNA may not be complete in packaging cells. Conclusion: FⅨ intron 1 inserted in forward orientation in retroviral vectors can increase retroviral titer and the expression level of FⅨ in muscle cells.