Regulation of Sox2 in the pre-placodal cephalic ectoderm and central nervous system by enhancer N-4.

The development of various tissues originating from the cephalic placodes is accompanied by the expression of the Sox2 gene. This Sox2 expression initiates in the pre-placodal cephalic ectoderm, and is regulated by enhancer N-4, which also regulates Sox2 in the embryonic central nervous system (CNS) posterior to the diencephalon. As the regulation of enhancer N-4 in the ectoderm likely reflects that of the pre-placodal cell state, its regulatory elements were characterized.

Regulation of ocular lens development by Smad-interacting protein 1 involving Foxe3 activation.

Sip1, a Smad-binding zinc-finger homeodomain transcription factor, has essential functions in embryonic development, but its role in individual tissues and the significance of its interaction with Smad proteins have not been fully characterized. In the lens lineage, Sip1 expression is activated after lens placode induction, and as the lens develops, the expression is localized in the lens epithelium and bow region where immature lens fibers reside. The lens-lineage-specific inactivation of the Sip1 gene was performed using mice homozygous for floxed Sip1 that carry a lens-specific Cre recombinase gene.