Ets motifs are necessary for endothelial cell-specific expression of a 723-bp Tie-2 promoter/enhancer in Hprt targeted transgenic mice.
OBJECTIVE
Tie-2 is an endothelial cell-specific receptor tyrosine kinase that is involved in the remodeling of blood vessels and angiogenesis. Our goal was to characterize Tie-2 promoter function as a means of providing insight into the mechanisms of endothelial cell-specific gene regulation.


RESULTS
When targeted to the Hprt locus of mice, a small Tie-2 promoter fragment (containing a 300-bp intronic enhancer coupled upstream to a 423-bp core promoter) (T-short) directed widespread endothelial cell expression in vivo. The T-short promoter contains 2 clusters of Ets sites, one in the first exon, the other in the intronic enhancer. In cultured endothelial cells, a combined mutation of the Ets motifs resulted in a significant reduction in promoter activity. Consistent with these results, the same Ets mutations resulted in a loss of detectable expression of the T-short promoter in all vascular beds with the notable exception of the brain.


CONCLUSIONS
These results suggest that the T-short promoter contains information for widespread expression in the vascular tree, Ets sites are necessary for in vivo promoter activity, and the shorter Tie-2 fragment may be useful as a tool to direct heterologous gene expression within the intact endothelium.
Minami
Takashi
T
Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro Tokyo, 153-8904. minami@med.rcast.u-tokyo.ac.jp
Kuivenhoven
Jan Albert
JA
Evans
Valerie
V
Kodama
Tatsuhiko
T
Rosenberg
Robert D
RD
Aird
William C
WC
D020816:Amino Acid Motifs; D000818:Animals; D001921:Brain / Q000098:blood supply; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology* / Q000196:embryology / Q000502:physiology*; D015870:Gene Expression; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D007668:Kidney / Q000098:blood supply; D007763:Lac Operon / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D018919:Neovascularization, Physiologic / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D050783:Proto-Oncogene Proteins c-ets; D042787:Receptor, TIE-2 / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D015534:Trans-Activators; D014157:Transcription Factors; D007041:Hypoxanthine Phosphoribosyltransferase; D042787:Receptor, TIE-2