Appropriate Tissue- and Cell-specific Expression of a Single Copy Human Angiotensinogen Transgene Specifically Targeted Upstream of the HPRT Locus by Homologous Recombination

Abstract

Development of experimental models by genetic manipulation in mice has proven to be very useful in determining the significance of particular genes in the development of or susceptibility to hypertension. Advances in molecular genetics, transgenic mouse technology, and physiological measurements in mice provided an opportunity to go a step further and develop models to analyze the physiological significance of specific gene variants potentially causing hypertension. In this report, we describe the development of a human angiotensinogen transgenic mouse model generated by targeting the human angiotensinogen gene upstream of the mouse HPRT locus by homologous recombination. The main benefit of this transgenic mouse model is that the human angiotensinogen gene is inserted into the mouse genome as a single copy at a predefined locus and in a specific orientation-a process that can be repeated utilizing other variants of this gene. We establish the validity of this approach by showing that the hAGT hprt mice have normal tissue-and cell-specific expression of the human angiotensinogen gene and normally produce and process the hAGT protein at physiological levels.

PITT: Pronuclear Injection-Based Targeted Transgenesis, a Reliable Transgene Expression Method in Mice

“…however, this locus could be a potential site for PITT, since plenty of studies indicate that a single-copy transgene introduced into the Hprt locus through gene targeting in ES cells exhibits ubiquitous or tissue-specific expression [18,20,28,37,51,72].…”

“…in these loci [1,18,20,51,63,72,77]. Since expression of the targeted transgene from these loci is highly reproducible, they are frequently used for rigorous analysis of transgene expression [13,38,55,65,77].…”

Down Syndrome Expressed Protein; DSCR-1 Deters Cancer and Septic Inflammation

“…To determine whether the DSCR-1s promoter region directed inducible expression in vivo, the -1664/+83 DSCR-1s promoter was coupled to the lacZ reporter gene and targeted the resulting transgenic cassette (DSCR-1-lacZ) to the Hprt locus of mice using homologous recombination. The Hprt-locus in vivo promoter analysis system has been previously shown to be beneficial in controlling and avoiding the undesirable and undetectable effects of copy number and integration site on promoter activity (Cvetkovic et al, 2000;Ryan and Sigmund, 2003). We have used this system successfully to show the vascular bed specific expression patterns of endothelial cell specific promoters, Flt-1, vWF, ROBO4, and Tie-2 (Minami et al, 2002;Minami et al, 2003;Okada et al, 2007).…”

Transgenic modelling of cytokine polarization in the lung

“…Transgene expression using cell-specific promoters further provides a great advantage for the accurate evaluation of gene function in an organ-specific or cell-specific manner. Furthermore, stable expression of the transgene can be achieved by targeted insertion of the transgene in permissive chromosomal loci, such as Rosa 26 or HPRT, by homologous recombination [9][10][11][12][13] . In addition, investigators have developed transgenic systems in which transgene expression can be externally regulated by tetracycline-responsive elements such as the one described below.…”