Developmental regulation and cell type-specific expression of the murine gamma F-crystallin gene is mediated through a lens-specific element containing the gamma F-1 binding site

Abstract

The mouse gamma F-crystallin gene, one of six differentially regulated members of the gamma-crystallin gene family, is expressed exclusively in central nuclear fiber cells of the adult lens. The expression of this gene is controlled through regulatory elements contained in two upstream enhancers and the proximal promoter. Here we show that while the upstream enhancers and the proximal promoter could each direct gene expression in fiber cells formed at early stages of lens growth and development, cooperation between these elements is required to achieve expression in fiber cells formed at later stages. Evidence is provided that cooperative interaction between these elements modulates gene expression by increasing promoter strength. We also show that sequences within the proximal promoter region that bind lens cell nuclear factor gamma F-1 are sufficient to elicit gene expression in central nuclear fiber cells of the adult lens.