The TGF-beta pseudoreceptor gene Bambi is dispensable for mouse embryonic development and postnatal survival.
The Bambi (Bmp and activin membrane-bound inhibitor) gene encodes a transmembrane protein highly similar in amino acid sequence to transforming growth factor-beta (TGF-beta receptors, however, the Bambi intracellular domain is short and lacks a serine/threonine-kinase domain that is essential for transducing TGF beta signaling. Previous biochemical assays showed that Bambi interacts directly with BMP receptors and antagonizes BMP signaling. Interestingly, the expression of Bambi largely overlaps, both temporally and spatially, with that of Bmp4 during early embryonic development in Xenopus, zebrafish, and mice, which led to the hypothesis that Bambi may function to regulate BMP signaling during embryogenesis. To directly analyze the roles of Bambi during embryonic development, we generated mice carrying a conditional allele of Bambi, Bambi(flox), with loxP sequences flanking the first exon that encodes the N-terminus and signal peptide region of the Bambi protein. Mice homozygous for this targeted conditional allele appear normal and fertile. We crossed the Bambi(flox)/+ mice to the EIIa-Cre transgenic mice and generated mice carrying deletion of the first exon of the Bambi gene. Surprisingly, mice homozygous for the deleted allele were viable, fertile and did not exhibit any discernible developmental defect. Our data exclude an essential role for Bambi in mouse embryonic development and postnatal survival.
Chen
Jianquan
J
Bush
Jeffrey O
JO
Ovitt
Catherine E
CE
Lan
Yu
Y
Jiang
Rulang
R
D000483:Alleles; D000818:Animals; D015139:Blotting, Southern; D003433:Crosses, Genetic; D004622:Embryo, Mammalian / Q000166:cytology; D053595:Embryonic Stem Cells / Q000378:metabolism; D005260:Female; D018390:Gene Targeting; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D019426:Integrases / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout / Q000196:embryology; D008822:Mice, Transgenic; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D015996:Survival Rate; D016212:Transforming Growth Factor beta / Q000235:genetics*
C485672:Bambi protein, mouse; D008565:Membrane Proteins; D016212:Transforming Growth Factor beta; C045073:Cre recombinase; D019426:Integrases