title: Cyclic expression of esr9 gene in Xenopus presomitic mesoderm.
abstract: During somitogenesis, the cycling expression of members of the Notch signalling cascade is involved in a segmentation clock that regulates the periodic budding of somites in chicken, mouse, and zebrafish. In frog, genes with cycling expression in the presomitic mesoderm have not been reported. Here, we describe the expression of Xenopus esr9 and esr10, two new members of the Hairy/Enhancer of split related family of bHLH proteins. We show that they are expressed in a highly dynamic fashion, with their mRNA levels oscillating periodically in the presomitic mesoderm during somitogenesis. This dynamic expression is independent of de novo protein synthesis. Thus, expression of esr9 and esr10 is an indicator of the segmentation clock in the amphibian embryo. This confirms the evolutionary conservation of a molecular pathway involved in vertebrate segmentation clock.
authors.affiliation: Division of Molecular Embryology, Deutches Krebsforschungszentrum, Heidelberg, Germany.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Ursula
authors.initials: U
authors.lastname: Fenger
authors.forename: Christof
authors.initials: C
authors.lastname: Niehrs
authors.forename: Nicolas
authors.initials: N
authors.lastname: Pollet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018507:Gene Expression Regulation, Developmental; D018257:Helix-Loop-Helix Motifs; D017403:In Situ Hybridization; D008648:Mesoderm / Q000502:physiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D019170:Somites / Q000502:physiology*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism
chemical_list: D014157:Transcription Factors; D029867:Xenopus Proteins; C479875:hes5.5 protein, Xenopus; C479874:hes5.7 protein, Xenopus