Species-specific detection of growth factor gene expression in developing murine prostatic tissue.

The aim of the present study was to develop a method by which the expression of paracrine signaling molecules could be localized to either epithelial or stromal cells of developing prostatic tissue. Heterospecific tissue recombinants composed of mouse urogenital epithelium (mouse UGE) plus rat urogenital mesenchyme (rat UGM) and the reciprocal tissue recombinants, rat urogenital epithelium (rat UGE) plus mouse urogenital mesenchyme (mouse UGM), were grafted under the renal capsule in intact, athymic male mouse and rat hosts. After 2 wk of growth, RNA from the grafts was analyzed by species-specific reverse transcription-polymerase chain reaction for the expression of the mRNA for the following molecules: transforming growth factors beta1, beta3, and alpha; epidermal growth factor; epidermal growth factor receptor; and keratinocyte growth factor. The species of expression of these growth factor and receptor gene products within the heterospecific tissue recombinants was identified, allowing determination of the cell layer in which the genes were expressed. Identification of the tissue-specific expression of the growth factor and growth factor receptor profiles of the epithelium and mesenchyme of this in vivo model provides a basis for understanding the autocrine and paracrine mediators of cell-cell interactions in prostatic development.