Tbx24, encoding a T-box protein, is mutated in the zebrafish somite-segmentation mutant fused somites

Nikaido, Masataka; Kawakami, Koichi; Sawada, Atsushi; Furutani-Seiki, Makoto; Takeda, Hiroyuki; Araki, Kazuo

doi:10.1038/ng899

Cited by 146 publications

(166 citation statements)

References 29 publications

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“…4A-F), as typically observed in embryos defective in the segmentation process Sawada et al 2001;Holley et al 2002). In contrast, the expression of fss/tbx24, which is normally expressed uniformly in the anterior and intermediate PSM (Nikaido et al 2002), was not affected (Fig. 4G,H).…”

Section: Resultsmentioning

confidence: 76%

Zebrafish Hairy/Enhancer of split protein links FGF signaling to cyclic gene expression in the periodic segmentation of somites

Kawamura¹,

Koshida²,

Hijikata³

et al. 2005

Genes Dev.

108

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Notch and fibroblast growth factor (FGF) signaling pathways have been implicated in the establishmentSomites are the morphologically distinct segmental units that are transiently formed during early vertebrate development and subsequently give rise to metameric and fundamental structures such as the vertebrae of the axial skeleton, their associated muscles, and tendons. The somites are subdivided from the anterior end of the unsegmented paraxial mesoderm, called the presomitic mesoderm (PSM), and sequentially generated in an anterior to posterior direction in a rhythmic fashion at regular spatiotemporal intervals. The molecular mechanism underlying the periodical formation of somites is coupled to an internal oscillator, referred to as the "segmentation clock", which has been evidenced by the cyclic expression of genes in the PSM (Palmeirim et al. 1997;Maroto and Pourquie 2001). Most genes that exhibit a cyclic expression pattern in the PSM are involved in the Notch signaling pathway . Various hairy/Enhancer of split (Espl)-related basic helix-loop-helix (bHLH) genes (hairy-1, hairy-2, and Hey2 in the chicken; Hes1, Hes5, Hes7, and Hey2 in the mouse; her1 and her7 in the zebrafish) that are transcriptional targets of the Notch signaling are expressed in a dynamic pattern of stripes across the PSM in a posterior to anterior direction. In addition, Lunatic fringe, encoding a glycosyltransferase that modulates the Notch signaling in the chicken and mouse, and the Notch ligand deltaC in the zebrafish also show an oscillatory expression pattern in the PSM. These cyclic genes, as well as other components of the Notch signaling pathway, were shown to be required for the proper somite segmentation in mice ( The oscillating and anteriorly propagating wave of gene expression, which is maintained in the posterior PSM, becomes fixed to cause segmentation in the anterior PSM. Activity gradients of signaling molecules, including fibroblast growth factor (FGF), Wnt, and retinoic acid are proposed to regulate the differentiation of PSM cells along the anteroposterior axis from a state permitting the oscillating gene expression to a state driving the segmentation program (Dubrulle et al. 2001;Sawada et al. 2001;Aulehla et al. 2003;Moreno and Kintner 2004). For instance, FGF signaling is the highest at the posterior end of the PSM with a gradual decrease toward the anterior, suggesting a role for FGF signaling in maintaining the characteristics of the posterior PSM cells (Dubrulle et al. 2001;Sawada et al. 2001). In fact, overexpression of FGF8 in the entire PSM of chick embryos causes an increase in the expression of Brachyury in the posterior PSM and suppresses morphological segmentation (Dubrulle et al. 2001). Furthermore, transient activation or inhibition of FGF signaling results in the formation of smaller or larger somites, respectively. Thus, FGF signaling appears to maintain the posterior characteristics, which allows the cyclic gene expression, and the level of FGF activity regulates the transition of the posterior PSM ...

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Section: Resultsmentioning

confidence: 76%

Zebrafish Hairy/Enhancer of split protein links FGF signaling to cyclic gene expression in the periodic segmentation of somites

Kawamura¹,

Koshida²,

Hijikata³

et al. 2005

Genes Dev.

108

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“…Oscillation of Notch signaling components (such as her1 and deltaC in zebrafish) in the PSM functions as the basic mechanism of the clock (5), whereas FGF, Wnt, and RA contribute to the stabilization of oscillating prepatterns and determine the spatial position and maturation state of presomitic primordia (10)(11)(12). Further, the transcription factor fss͞tbx24 is required for the induction of segmentation genes such as mesp-a and PAPC, as well as for the stabilization of oscillating genes (9). The important question remains how presomitic cells differentiate from the immature to the mature state.…”

Section: Discussionmentioning

confidence: 99%

“…Cyclic expression of genes such as her1 and deltaC in the posterior PSM is disorganized in these Notch pathway mutants. In the mutant fss that encodes the T-box factor 24 (Tbx24) (9), most of the anterior her1 strip is missing, but her1 oscillations in the posterior PSM occur normally. Thus, fss may not be required to generate cyclic gene expression but may be required to stabilize such expression in the anterior PSM.…”

mentioning

confidence: 99%

Zebrafish GADD45 β genes are involved in somite segmentation

Kawahara

Che

Hanaoka

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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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 gadd45␤1 and gadd45␤2 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 gadd45␤ genes caused somite defects with different consequences for marker gene expression. Knockdown of gadd45␤ 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 gadd45␤1 or gadd45␤2 suppressed expression of mesp-a and her1 in anterior PSM and MyoD in paraxial mesoderm. These results indicate that regulated expression of gadd45␤ genes in the anterior PSM is required for somite segmentation.presomitic mesoderm ͉ periodicity ͉ patterning ͉ knockdown

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“…The Bowline/ripply family proteins mediate interactions between Tbx6/ tbx24, which are transcriptional activators that are commonly required for somite segmentation program (Nikaido et al, 2002;Yasuhiko et al, 2006), and the transcriptional corepressors XGrg-4/Groucho Kawamura et al, 2008). At the end of somitogenesis, it is likely that this interaction results in the suppression of Tbx6/tbx24-dependent transcription of genes that are essential for the somite segmentation program.…”

Section: Identification and Characterization Of Novel Somitogenesis-rmentioning

confidence: 99%

In vitro organogenesis from undifferentiated cells in Xenopus

Asashima

Ito

Chan

et al. 2009

Developmental Dynamics

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Amphibians have been used for over a century as experimental animals. In the field of developmental biology in particular, much knowledge has been accumulated from studies on amphibians, mainly because they are easy to observe and handle. Xenopus laevis is one of the most intensely investigated amphibians in developmental biology at the molecular level. Thus, Xenopus is highly suitable for studies on the mechanisms of organ differentiation from not only a single fertilized egg, as in normal development, but also from undifferentiated cells, as in the case of in vitro organogenesis. Based on the established in vitro organogenesis methods, we have identified many genes that are indispensable for normal development in various organs. These experimental systems are useful for investigations of embryonic development and for advancing regenerative medicine. Developmental Dynamics 238:1309 -1320, 2009.

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Tbx24, encoding a T-box protein, is mutated in the zebrafish somite-segmentation mutant fused somites

Cited by 146 publications

References 29 publications

Zebrafish Hairy/Enhancer of split protein links FGF signaling to cyclic gene expression in the periodic segmentation of somites

Zebrafish Hairy/Enhancer of split protein links FGF signaling to cyclic gene expression in the periodic segmentation of somites

Zebrafish GADD45 β genes are involved in somite segmentation

In vitro organogenesis from undifferentiated cells in Xenopus

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