A developmentally regulated basic-leucine zipper-like gene and its expression in embryonic retina and lens.

Transcriptional regulators play important roles in the control of key developmental events. We have identified sw3-3, a likely candidate for such a function, in tissues of the eye and other neural organs. It encodes a basic-leucine zipper-like protein, in which two leucine zipper motifs flank a basic domain. The latter contains helix-disturbing amino acids such as glycine and proline, at positions occupied by conserved asparagine and alanine residues (respectively) in "conventional" basic-leucine zipper proteins. sw3-3 is widely expressed at early embryonic stages in the lens, retina, and other neural tissues and is down-regulated thereafter with a spatial and temporal pattern that correlates with the cessation of mitotic activity and the onset of cell migration and differentiation.