title: Mesp2: a novel mouse gene expressed in the presegmented mesoderm and essential for segmentation initiation.
abstract: We isolated a novel bHLH protein gene Mesp2 (for mesoderm posterior 2) that cross-hybridizes with Mesp1 expressed in the early mouse mesoderm. Mesp2 is expressed in the rostral presomitic mesoderm, but down-regulated immediately after the formation of the segmented somites. To determine the function of MesP2 protein (MesP2) in somitogenesis, we generated Mesp2-deficient mice by gene targeting. The homozygous Mesp2 (-/-) mice died shortly after birth and had fused vertebral columns and dorsal root ganglia, with impaired sclerotomal polarity. The earliest defect in the homozygous embryos was a lack of segmented somites. Their disruption of the metameric features, altered expression of Mox-1, Pax-1, and Dll1, and lack of expression of Notch1, Notch2, and FGFR1 suggested that MesP2 controls sclerotomal polarity by regulating the signaling systems mediated by notch-delta and FGF, which are essential for segmentation.
authors.affiliation: Banyu Tsukuba Research Institute (Merck), Japan. saga@nihs.go.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Saga
authors.forename: N
authors.initials: N
authors.lastname: Hata
authors.forename: H
authors.initials: H
authors.lastname: Koseki
authors.forename: M M
authors.initials: MM
authors.lastname: Taketo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D001842:Bone and Bones / Q000002:abnormalities; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005314:Embryonic and Fetal Development / Q000235:genetics*; D005346:Fibroblast Growth Factors / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D006720:Homozygote; D008565:Membrane Proteins / Q000235:genetics; D008648:Mesoderm; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D051880:Receptors, Notch; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D018076:DNA, Complementary; D005346:Fibroblast Growth Factors; D008565:Membrane Proteins; D051880:Receptors, Notch; D014157:Transcription Factors; C107407:Mesp2 protein, mouse