Integration and expression of GFP gene directed by the erythroid-specific element in transgenic mice

摘要

To study the relationship between integration status and expression level of the foreign gene, copy number of the foreign green fluorescence protein (GFP) gene directed by the erythroid-specific elements (HS2 and HS3) in transgenic mice were determined by real-time quantitative PCR, and the GFP expression level in peripheral blood was measured by fluorescence-activated cell sorter (FACS) analysis and was observed under a fluorescence microscope. The integrated sites of foreign gene in two transgenic mice were detected using fluorescene in situ hybridization (FISH). The results showed that the copy numbers of the foreign gene were different and varied greatly in various transgenic mouse lines. The copy number in one transgenic mouse (GFP-19) was as high as 63, and only two copies of foreign gene were detected in another transgenic mouse (GFP-75). Moreover, statistic analysis indicated that the copy numbers was not correlated with the expression level of GFP gene ( r ＝ - 0.29684 ， P =0.4379) . FISH analysis suggested that the foreign genes were integrated in the different chromosomes of the two transgenic mice, and the intensity of hybridization signals was coincident with the copies of GFP gene. We concluded that the expression level of foreign genes in transgenic mice may rely more on integration sites on chromosomes than copy numbers[ Acta Zoologica Sinica 50 (2): 263 - 268 , 2004].