title: Live in vivo imaging of Egr-1 promoter activity during neonatal development, liver regeneration and wound healing.
abstract: BACKGROUND
  The zinc finger transcription factor Egr-1 (Early growth response 1) is central to several growth factors and represents an important activator of target genes not only involved in physiological processes like embryogenesis and neonatal development, but also in a variety of pathophysiological processes, for example atherosclerosis or cancer. Current options to investigate its transcription and activation in vivo are end-point measurements that do not provide insights into dynamic changes in the living organism.
  
  
  RESULTS
  We developed a transgenic mouse (Egr-1-luc) in which the luciferase reporter gene is under the control of the murine Egr-1 promoter providing a versatile tool to study the time course of Egr-1 activation in vivo. In neonatal mice, bioluminescence imaging revealed a high Egr-1 promoter activity reaching basal levels three weeks after birth with activity at snout, ears and paws. Using a model of partial hepatectomy we could show that Egr-1 promoter activity and Egr-1 mRNA levels were increased in the regenerating liver. In a model of wound healing, we demonstrated that Egr-1 promoter activity was upregulated at the site of injury.
  
  
  CONCLUSIONS
  Taken together, we have developed a transgenic mouse model that allows real time in vivo imaging of the Egr-1 promoter activity. The ability to monitor and quantify Egr-1 activity in the living organism may facilitate a better understanding of Egr-1 function in vivo.
authors: Walter-Brendel-Centre of Experimental Medicine, Ludwig-Maximilians-University, Munich, Germany.
authors: Philipp
authors: P
authors: Dussmann
authors: Judith I
authors: JI
authors: Pagel
authors: Sabina
authors: S
authors: Vogel
authors: Terese
authors: T
authors: Magnusson
authors: Rene
authors: R
authors: Zimmermann
authors: Ernst
authors: E
authors: Wagner
authors: Wolfgang
authors: W
authors: Schaper
authors: Manfred
authors: M
authors: Ogris
authors: Elisabeth
authors: E
authors: Deindl
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