Alx4, a stromally-restricted homeodomain protein, is required for normal mammary epithelial morphogenesis.
Published: 2006
Language: eng
Number of pages: 69
ISBN-13: 9780494163603
Description: Mammary gland development is governed by the interplay between regulation by systemic hormones and reciprocal epithelial-stromal interactions. The homeodomain transcription factor, Alx4, is expressed in the mesenchyme of a number of mouse tissues whose development depends on epithelial-mesenchymal interactions. We demonstrate here that Alx4 is expressed in a subset of ERalpha-expressing stromal cells adjacent to terminal end buds (TEBs) and alveoli in the murine mammary gland during puberty and pregnancy, respectively. Furthermore, Alx4 expression is induced by estrogen following 17beta-estradiol administration into prepubescent animals. The importance of Alx4 during mammary gland development was determined using mice homozygous for the functionally-null allele of Alx4,  lstD. In these mice, pubescent mammary glands exhibit impaired ductal morphogenesis with distorted ductal architecture, defective TEB formation and bifurcation. The number of TEBs and branch points in Alx4 lstD/lstD mammary glands were significantly reduced. Ductal defects were retained in mutant adult virgins, but side-branching during pregnancy was unaffected.
Notes: Source: Masters Abstracts International, Volume: 44-06, page: 2773.

Thesis (M.Sc.)--University of Toronto, 2006.

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