Regulation of delta-crystallin expression: an investigation by transfer of the chicken gene into mouse cells.

In order to understand how crystallin genes are regulated so that they would be expressed with a high lens specificity, we introduced a cloned delta-crystallin gene of the chicken and its derivatives into various mouse cells. In such a heterologous combination of the gene and the recipient cells, chicken delta-crystallin was expressed in lens cells with a high preference over other cell types. The high expression in the lens is basically ascribed to interactions between the putative lens-specific mechanisms for transcription and the base pairs from -80 to +35 encompassing the transcriptional initiation site of the delta-crystallin gene. A non-specific low expression was also observed. This may account for ectopic delta-crystallin expression which takes place in certain non-lenticular embryonic tissues of the chicken.