Regulation of <i>Msx-1, Msx-2, Bmp-2</i> and <i>Bmp-4</i> during foetal and postnatal mammary gland development

TLDR

Msx‑1 and Msx‑2 homeobox genes are coordinately regulated with Bmp‑2 and Bmp‑4 ligands in various developing tissues. During foetal and postnatal mammary gland development, Msx‑1, Msx‑2, Bmp‑2, and Bmp‑4 transcripts are developmentally regulated, with Msx‑2 expression modulated by estrogen and ovariectomy, indicating that Msx and Bmp genes likely control epithelial‑mesenchymal interactions in mammary development.

Abstract

ABSTRACT Expression of the Msx-1 and Msx-2 homeobox genes have been shown to be co-ordinately regulated with the Bmp-2 and Bmp-4 ligands in a variety of developing tissues. Here we report that transcripts from all four genes are developmentally regulated during both foetal and postnatal mammary gland development. The location and timecourse of the Bmp and Msx expression point to a role for Msx and Bmp gene products in the control of epithelialmesenchymal interactions. Expression of Msx-2, but not Msx-1, Bmp-2 or Bmp-4 was decreased following ovariectomy, while expression of the human Msx-2 homologue was regulated by 17β-oestradiol in the MCF-7 breast cancer cell line. The regulation of Msx-2 expression by oestrogen raises the possibility that hormonal regulation of mammary development is mediated through the control of epithelialmesenchymal interactions.