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- Chengyu Liu
- Alkek Institute of Biosciences and Technology, Texas A&M System Health Science Center, 2121 Holcombe Blvd, Houston, TX 77030, USA
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- Wei Liu
- Alkek Institute of Biosciences and Technology, Texas A&M System Health Science Center, 2121 Holcombe Blvd, Houston, TX 77030, USA
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- Mei-Fang Lu
- Alkek Institute of Biosciences and Technology, Texas A&M System Health Science Center, 2121 Holcombe Blvd, Houston, TX 77030, USA
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- Nigel A. Brown
- Department of Anatomy and Developmental Biology, St. George’s Hospital Medical School, University of London, Cranmer Terrace, London SW17 0RE, UK
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- James F. Martin
- Alkek Institute of Biosciences and Technology, Texas A&M System Health Science Center, 2121 Holcombe Blvd, Houston, TX 77030, USA
抄録
<jats:p>Although much progress has been made in understanding the molecular mechanisms regulating left-right asymmetry, the final events of asymmetric organ morphogenesis remain poorly understood. The phenotypes of human heterotaxia syndromes, in which organ morphogenesis is uncoupled, have suggested that the early and late events of left-right asymmetry are separable. The Pitx2 homeobox gene plays an important role in the final stages of asymmetry. We have used two new Pitx2 alleles that encode progressively higher levels of Pitx2c in the absence of Pitx2a and Pitx2b, to show that different organs have distinct requirements for Pitx2c dosage. The cardiac atria required low Pitx2c levels, while the duodenum and lungs used higher Pitx2c doses for normal development. As Pitx2c levels were elevated, the duodenum progressed from arrested rotation to randomization, reversal and finally normal morphogenesis. In addition, abnormal duodenal morphogenesis was correlated with bilateral expression of Pitx2c. These data reveal an organ-intrinsic mechanism, dependent upon dosage of Pitx2c, that governs asymmetric organ morphogenesis. They also provide insight into the molecular events that lead to the discordant organ morphogenesis of heterotaxia.</jats:p>
収録刊行物
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- Development
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Development 128 (11), 2039-2048, 2001-06-01
The Company of Biologists