title: Zebrafish GADD45beta genes are involved in somite segmentation.
abstract: Somites in vertebrates are periodic segmented structures that give rise to the vertebrae and muscles of body. Somites are generated from presomitic mesoderm (PSM), but it is not fully understood how cellular differentiation and segment formation are achieved in the anterior PSM. We report here that zebrafish gadd45beta1 and gadd45beta2 genes are periodically expressed as paired stripes adjacent to the neural tube in the anterior PSM region where presomitic cells mature. In mammals, it is known that GADD45 (growth arrest and DNA damage) family proteins play a role in cell-cycle control. We found that both knockdown and overexpression of gadd45beta genes caused somite defects with different consequences for marker gene expression. Knockdown of gadd45beta genes with antisense morpholino oligonucleotides caused a broad expansion of mesp-a in the PSM, and both cyclic expression of her1 and segmented expression of MyoD were disorganized. On the other hand, injection of gadd45beta1 or gadd45beta2 suppressed expression of mesp-a and her1 in anterior PSM and MyoD in paraxial mesoderm. These results indicate that regulated expression of gadd45beta genes in the anterior PSM is required for somite segmentation.
authors.affiliation: Laboratory of Developmental Molecular Genetics, Horizontal Medical Research Organization, Kyoto University Faculty of Medicine, Yoshida, Sakyo-Ku, Kyoto 606-8501, Japan. atsuo@hmro.med.kyoto-u.ac.jp
authors.forename: Atsuo
authors.initials: A
authors.lastname: Kawahara
authors.forename: Yong-Suk
authors.initials: YS
authors.lastname: Che
authors.forename: Ryuki
authors.initials: R
authors.lastname: Hanaoka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takeda
authors.forename: Igor B
authors.initials: IB
authors.lastname: Dawid
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D048768:MAP Kinase Kinase Kinase 4 / Q000502:physiology; D008648:Mesoderm / Q000502:physiology; D008969:Molecular Sequence Data; D011506:Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D015398:Signal Transduction; D019170:Somites / Q000502:physiology*; D015027:Zebrafish; D000097642:GADD45 Proteins
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D048768:MAP Kinase Kinase Kinase 4; D011506:Proteins; D000097642:GADD45 Proteins