Abstract
lefty-1, lefty-2, and nodal are expressed on the left side of developing mouse embryos and are implicated in left-right (L-R) determination. The role of lefty-1 was examined by analyzing mutant mice lacking this gene. The lefty-1-deficient mice showed a variety of L-R positional defects in visceral organs. Unexpectedly, however, the most common feature of lefty-1-/- mice was thoracic left isomerism (rather than right isomerism). The lack of lefty-1 resulted in bilateral expression of nodal, lefty-2, and Pitx2 (a homeobox gene normally expressed on the left side). These observations suggest that the role of lefty-1 is to restrict the expression of lefty-2 and nodal to the left side, and that lefty-2 or nodal encodes a signal for "leftness."
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Animals, Newborn
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Body Patterning / genetics*
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Gene Expression Regulation, Developmental*
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Homeobox Protein PITX2
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Homeodomain Proteins / biosynthesis
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Homeodomain Proteins / genetics
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Left-Right Determination Factors
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Lung / abnormalities
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Mice
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Mice, Inbred C3H
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Mice, Inbred C57BL
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Mice, Knockout
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Mice, Transgenic
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Mutation
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Nodal Protein
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Nuclear Proteins*
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Paired Box Transcription Factors
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Proteins / genetics*
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Proteins / physiology*
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Transcription Factors / biosynthesis
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Transcription Factors / genetics
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Transforming Growth Factor beta / deficiency
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Transforming Growth Factor beta / genetics*
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Transforming Growth Factor beta / physiology*
Substances
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Homeodomain Proteins
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Left-Right Determination Factors
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Nodal Protein
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Nodal protein, mouse
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Nuclear Proteins
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Paired Box Transcription Factors
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Proteins
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Transcription Factors
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Transforming Growth Factor beta
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homeobox protein PITX1
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homeobox protein PITX3