Abstract
Paraxial mesoderm in vertebrates gives rise to all trunk and limb skeletal muscles, the trunk skeleton, and portions of the trunk dermis and vasculature. We show here that germline deletion of mouse pMesogenin1, a bHLH class gene specifically expressed in developmentally immature unsegmented paraxial mesoderm, causes complete failure of somite formation and segmentation of the body trunk and tail. At the molecular level, the phenotype features dramatic loss of expression within the presomitic mesoderm of Notch/Delta pathway components and oscillating somitic clock genes that are thought to control segmentation and somitogenesis. Subsequent patterning and specification steps for paraxial mesoderm also fail, leading to a complete absence of all trunk paraxial mesoderm derivatives, which include skeletal muscle, vertebrae, and ribs. We infer that pMesogenin1 is an essential upstream regulator of trunk paraxial mesoderm development and segmentation.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Abnormalities, Multiple
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Animals
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Basic Helix-Loop-Helix Transcription Factors
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Cell Differentiation / genetics
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Embryonic and Fetal Development / genetics
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Female
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Fetal Proteins*
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Fungal Proteins / genetics
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Fungal Proteins / metabolism
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Gene Expression Regulation, Developmental
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Glycosyltransferases*
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Helix-Loop-Helix Motifs
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Homozygote
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Male
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Mesoderm / pathology*
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Mesoderm / physiology*
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Mice
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Mice, Inbred Strains
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Mice, Mutant Strains
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Proteins / genetics
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Proteins / metabolism
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Receptors, Notch
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Recombination, Genetic
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Saccharomyces cerevisiae Proteins*
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Signal Transduction
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T-Box Domain Proteins / genetics
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T-Box Domain Proteins / metabolism
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Tail / abnormalities
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Transcription Factors / genetics*
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Transcription Factors / metabolism
Substances
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Basic Helix-Loop-Helix Transcription Factors
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Fetal Proteins
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Fungal Proteins
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HES1 protein, S cerevisiae
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Membrane Proteins
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Msgn1 protein, mouse
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Proteins
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Receptors, Notch
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Saccharomyces cerevisiae Proteins
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T-Box Domain Proteins
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Transcription Factors
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Glycosyltransferases
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Lfng protein, mouse
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Brachyury protein