The structure and function of a regulatory gene, WOODEN LEG (WOL), is described. The WOL gene is expressed specifically in the vasculature during early stages of embryogenesis with expression continuing throughout development. WOL encodes a novel two component signal transducer and is required for asymmetric cell divisions during vascular tissue morphogenesis. Also described are WOL nucleic acids, WOL gene products, (including, but not limited to, transcriptional products such as mRNAs, antisense, and ribozyme molecules, and translational products such WOL proteins, polypeptides, peptides and fusion proteins related thereto), antibodies to WOL gene products, WOL promoters and regulatory regions and the use of the foregoing to improve agronomically valuable plants.