Goodart S A, Huynh C, Chen W, Cooper A D, Levy-Wilson B
Research Institute, Palo Alto Medical Foundation, Palo Alto, California 94301, USA.
Biochem Biophys Res Commun. 1999 Dec 20;266(2):454-9. doi: 10.1006/bbrc.1999.1799.
We have generated transgenic mice expressing human CYP7A1 transgenes. Only 1.5 kilobases (kb) of 5' upstream sequence and 6.5 kb of 3' sequence were sufficient for hepatic transcription of the transgenes. However, the 5' end segment alone was not sufficient to direct liver expression, suggesting that additional hepatic regulatory elements reside in the 3' extension or within introns. The level of expression of these transgenes was low in comparison to the levels of the endogenous mouse CYP7A1 mRNA. To generate mice expressing higher levels of CYP7A1 mRNA, we injected a large human genomic PAC clone, extending up to -105 kb 5' of the structural gene and about 50 kb 3' of the gene. These transgenic mice expressed CYP7A1 mRNA at higher levels, suggesting that additional hepatic regulatory elements are found either 5' of -1520 or beyond 6.5 kb 3' of the gene.
我们已经培育出了表达人CYP7A1转基因的转基因小鼠。仅1.5千碱基（kb）的5'上游序列和6.5 kb的3'序列就足以实现转基因的肝脏转录。然而，仅5'末端片段不足以指导肝脏表达，这表明额外的肝脏调控元件存在于3'延伸区或内含子内。与内源性小鼠CYP7A1 mRNA的水平相比，这些转基因的表达水平较低。为了培育出表达更高水平CYP7A1 mRNA的小鼠，我们注射了一个大型人类基因组PAC克隆，其延伸至结构基因5'端上游-105 kb处以及基因3'端约50 kb处。这些转基因小鼠表达的CYP7A1 mRNA水平更高，这表明在-1520的5'端之前或基因3'端6.5 kb之外发现了额外的肝脏调控元件。
