In situ Detection of $\beta $-Galactosidase in Lenses of Transgenic Mice with a $\gamma $-Crystallin/lacZ Gene

Transgenic mice carrying the $\gamma $2-crystallin promoter fused to the coding region of the bacterial lacZ gene were generated. The offspring of three founder mice expressed high levels of the enzyme solely in the central nuclear fiber cells of the lens as measured by an in situ assay for the detection of $\beta $-galactosidase activity. These results suggest that $\gamma $2-crystallin sequences between -759 to +45 contain essential information required for appropriate tissue-specific and temporal regulation of the mouse $\gamma $2-crystallin gene. In a broader context, this study also demonstrates the utility of $\beta $-galactosidase hybrid gene constructs for monitoring the activity of gene regulatory elements in transgenic mice.