Transcriptional targets of the vitamin D3 receptor-mediating cell cycle arrest and differentiation.

We are exploring the mechanism of action of the hormonal form of the nutrient vitamin D, 1,25(OH)2D3, and its cognate nuclear receptor at the level of gene control. In doing so, we have focused on a dual track as follows: 1) to define the vitamin D3 receptor (VDR) function and structure by examining its various actions at the molecular level; and 2) to isolate and characterize VDR target genes that might be playing key roles in mediating vitamin D growth suppression and differentiation in responsive cells, specifically, the elucidation of vitamin D target genes as they relate to myeloid differentiation. Here, we will summarize some of our recent results from both tracks because a detailed understanding of how VDR functions as a ligand-regulated transcription factor will allow us to study its actions on these newly discovered genes more effectively.