The abundance of δ-crystallin in the chicken eye lens provides an advantageous marker for tissue-specific gene expression during cellular differentiation. The lens-specific expression of the δ1-crystallin gene is governed by an enhancer in the third intron, which binds a positive (δEF2) and negative (δEF1) factor in its core region. Here we show by DNase I footprinting, electrophoretic mobility-shift assays, and cotransfection experiments with the δ1-promoter/enhancer fused to the chloramphenicol acetyltransferase reporter gene that the δ1-crystallin enhancer has two adjacent functional Pax-6 binding sites. We also demonstrate by DNase I footprinting that the δEF1 site can bind the transcription factor USF, raising the possibility that USF may cooperate with Pax-6 in activation of the chicken δ1- and αA-crystallin genes. These data, coupled with our recent demonstration that Pax-6 activates the αA-crystallin gene, suggest that Pax-6 may have been used extensively throughout evolution to recruit and express crystallin genes in the lens.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - May 9 1995|
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