lefty-1 is required for left-right determination as a regulator of lefty-2 and nodal.
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."
Division of Molecular Biology, Institute for Molecular and Cellular Biology, Osaka University, Suita, Japan.
C
C
Meno
A
A
Shimono
Y
Y
Saijoh
K
K
Yashiro
K
K
Mochida
S
S
Ohishi
S
S
Noji
H
H
Kondoh
H
H
Hamada
D000818:Animals; D000831:Animals, Newborn; D019521:Body Patterning / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics; D055458:Left-Right Determination Factors; D008168:Lung / Q000002:abnormalities; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009154:Mutation; D055457:Nodal Protein; D009687:Nuclear Proteins; D051761:Paired Box Transcription Factors; D011506:Proteins / Q000235:genetics* / Q000502:physiology*; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000172:deficiency / Q000235:genetics* / Q000502:physiology*; D000097577:Homeobox Protein PITX2
D018398:Homeodomain Proteins; D055458:Left-Right Determination Factors; D055457:Nodal Protein; D009687:Nuclear Proteins; D051761:Paired Box Transcription Factors; D011506:Proteins; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D000097577:Homeobox Protein PITX2; C526008:Nodal protein, mouse; C101485:homeobox protein PITX1; C433629:homeobox protein PITX3