摘要
The way in which spatially patterned cellular identities are generated is a central question of organogenesis. In the case of Drosophila heart formation, the cardiac progenitors are specified in precise mesodermal positions, giving rise to multiple cell types in a highly ordered arrangement. Here, we study the mechanisms by which positional information conveyed by signaling pathways and a combinatorial code of activating and repressing transcription factors work together to confine the expression of the homeobox gene even-skipped (eve) to a small region of the dorsal mesoderm. By manipulating both expression patterns and binding sites for transcription factors, we show that a complex combination of regulatory activities converge on a single enhancer of eve to generate precisely targeted gene expression within the cardiac mesoderm. In particular, ladybird early (lbe), a homeobox gene expressed adjacent to eve, restricts the positive actions of factors downstream of wingless, decapentaplegic, and ras to generate the eve pattern. Mutation of a Lbe binding site causes dramatic expansion of expression and abolishes the responsiveness to repression by lbe. Conversely, eliminating eve in the mesoderm expands lbe expression into the normal eve-expressing territory, suggesting that mutual repression between eve and lbe is essential for delineating the spatial patterns of gene expression that specify cell types within the cardiac mesoderm.
原文 | 英語 |
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頁(從 - 到) | 225-240 |
頁數 | 16 |
期刊 | Developmental Biology |
卷 | 252 |
發行號 | 2 |
DOIs | |
出版狀態 | 已發佈 - 2002 |
ASJC Scopus subject areas
- 分子生物學
- 發展生物學
- 細胞生物學