The bHLH regulator pMesogenin1 is required for maturation and segmentation of paraxial mesoderm.
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.
Yoon
J K
JK
Division of Biology, California Institute of Technology, Pasadena, California 91125, USA.
Wold
B
B
D000015:Abnormalities, Multiple; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation / Q000235:genetics; D005314:Embryonic and Fetal Development / Q000235:genetics; D005260:Female; D005326:Fetal Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D016695:Glycosyltransferases; D018257:Helix-Loop-Helix Motifs; D006720:Homozygote; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008648:Mesoderm / Q000473:pathology* / Q000502:physiology*; D051379:Mice; D008815:Mice, Inbred Strains; D008817:Mice, Mutant Strains; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D051880:Receptors, Notch; D011995:Recombination, Genetic; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D020825:T-Box Domain Proteins / Q000235:genetics / Q000378:metabolism; D013623:Tail / Q000002:abnormalities; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D000098908:Brachyury Protein; D000098825:Oxysterol Binding Proteins
D051792:Basic Helix-Loop-Helix Proteins; D005326:Fetal Proteins; D005656:Fungal Proteins; D016695:Glycosyltransferases; D008565:Membrane Proteins; D011506:Proteins; D051880:Receptors, Notch; D029701:Saccharomyces cerevisiae Proteins; D020825:T-Box Domain Proteins; D014157:Transcription Factors; D000098908:Brachyury Protein; C087902:HES1 protein, S cerevisiae; D000098825:Oxysterol Binding Proteins; C410883:Msgn1 protein, mouse; C498392:Lfng protein, mouse