1. ^*Department of Dermatology, Columbia University, New York, USA
2. ^†School of Biological Sciences, Durham University, Durham, UK
3. ^‡Department of Genetics and Development, Columbia University, New York, USA

Correspondence: Ryan F. L. O'Shaughnessy, Department of Dermatology, College of Physicians and Surgeons, Columbia University, VC15-204, 630 W, 168th Street, New York, New York 10032, USA. Email: r.f.l.oshaughnessy@qmul.ac.uk

Received 13 January 2004; Revised 21 April 2004; Accepted 25 May 2004; Published online 10 September 2004.

Abstract

We used microarray hybridization to identify genes induced in the dermal papilla (DP) during anagen as a result of the interaction with epithelial matrix cells. We identified inhibitors of the bone morphogenetic protein (BMP) and transforming growth factor (TGF)-signalling pathway, as well as the rat homologue of the Xenopus-secreted WNT modulator Wise. A large number of genes previously determined to be expressed in the DP were shown to be expressed in both the DP and dermal sheath (DS). Genes induced in the DP during anagen included modulators of genes expressed additionally in the DS as well as specialized extracellular matrix components. Expression of some of these genes were lost when the DP cells were cultured, suggesting that their expression was interaction dependent. One such gene, the WNT-signalling modulator Wise, was expressed in the DP and not in the non-inductive DS and was additionally expressed at high levels in the precortex and in the putative bulge region. In addition to the reported WNT-signalling modulation role, we show that Wise reduced both BMP and TGF signalling in transformed fibroblasts. We speculate that loss of gene expression in cultured cells is a model for the loss of gene expression observed at catagen.