Targeting the Hprt locus in mice reveals differential regulation of Tie2 gene expression in the endothelium.
To study the in vivo expression of the murine Tie2 gene, we have targeted the hypoxanthine phosphoribosyltransferase (Hprt) gene locus to generate two single-copy transgenic mice: T1, containing the 2,100-bp Tie2 promoter upstream from the beta-galactosidase (LacZ) gene, and T5, which also included an enhancing element originating from the first intron of the Tie2 gene. Comparing T1 and T5 embryos at day E10.5 revealed differential endothelial cell-specific expression of LacZ, whereas colocalization analyses showed that the expression was confined to endothelial cells. Moderate reporter gene activity was observed in the brain and kidney of T1 adults, whereas extensive LacZ gene expression was seen in the vasculature of most organs of the T5 adults. This study demonstrates the feasibility of targeting the Hprt locus with endothelial cell-specific sequences to analyze the spatial-temporal expression of transgenes. Of particular importance is the observation that the analysis of a single transgene copy in a defined locus allows for an accurate and rapid comparison of transcriptional activity among regulatory DNA sequences.
Evans
V
V
Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts 02139, USA.
Hatzopoulos
A
A
Aird
W C
WC
Rayburn
H B
HB
Rosenberg
R D
RD
Kuivenhoven
J A
JA
D000818:Animals; D001921:Brain / Q000196:embryology / Q000378:metabolism; D002460:Cell Line; D002999:Clone Cells; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D004730:Endothelium, Vascular / Q000196:embryology / Q000378:metabolism*; D005240:Feasibility Studies; D005260:Female; D005786:Gene Expression Regulation; D018390:Gene Targeting; D017930:Genes, Reporter; D006580:Genetic Carrier Screening; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D007668:Kidney / Q000196:embryology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009928:Organ Specificity; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D042787:Receptor, TIE-2; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
D007041:Hypoxanthine Phosphoribosyltransferase; D020794:Receptor Protein-Tyrosine Kinases; D042787:Receptor, TIE-2; D001616:beta-Galactosidase