Expression of the mouse En- 2 gene in a band of cells across 
the midbrain- hindbrain junction. The 10-day transgenic 
embryo contains a lacZ reporter construct expressed from 
En-2 DNA regulatory sequences. The cells expressing lacZ 
( dark ) are visualized by histochemical staining of the 
lacZ gene product. 
From Sedivy, f., and foyner, A. 1992. Gene Targeting. 
New York: W.H. Freeman, p 161. 
506 
