Chapter 14 Generation of Body Plan Phenotypes in Early Embryogenesis

Kao, Ken; Danilchik, Michael V.

doi:10.1016/s0091-679x(08)60282-4

Cited by 15 publications

(10 citation statements)

References 37 publications

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“…Furthermore, the neural inducing properties of the chordamesoderm/organizer are inhibited in these embryos, resulting in little or no anterior neural tissue. Phenotypically similar aneural embryos are observed when formation of the chordamesoderm/organizer is inhibited by UV irradiation of fertilized Xenopus eggs (for review, see Kao and Danilchik 1991). Analysis of early gene transcripts suggests that the phenotypic effects of ⌬D overexpression can be explained by a down-regulation of essential mRNAs such as Xnot-2, Xbra, and gsc and possibly many others.…”

Section: Xqua Is Essential For Notochord Developmentmentioning

confidence: 99%

The KH domain protein encoded by quaking functions as a dimer and is essential for notochord development inXenopus embryos

Zorn¹,

Krieg²

1997

Genes Dev.

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Mutations in the mouse indicate that quaking gene function is essential for both embryogenesis and for development of the nervous system. Recent isolation of the mouse quaking gene identified a putative RNA-binding protein containing a single KH domain. We have previously isolated the Xenopus homolog of quaking, Xqua, and shown that the sequence is highly conserved through evolution. Here, we report experimental data on the biochemical function of the quaking protein and its role during development. We demonstrate that the quaking protein expressed during early embryogenesis, pXqua 357 , can bind RNA in vitro, and we have mapped the regions of the protein that are essential for RNA binding. We present evidence that pXqua can form homodimers and that dimerization may be required for RNA binding. Oocyte injection experiments show that pXqua 357 is located in both the nucleus and cytoplasm. In the Xenopus embryo, Xqua is first expressed during gastrulation in the organizer region and its derivative, the notochord. In later stage embryos, Xqua is expressed in a number of mesodermal and neural tissues. We demonstrate that disruption of normal Xqua function, by overexpression of a dominant inhibitory form of the protein, blocks notochord differentiation. Xqua function appears to be required for the accumulation of important mRNAs such as Xnot, Xbra, and gsc. These results indicate an essential role for the quaking RNA-binding protein during early vertebrate embryogenesis.

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Section: Xqua Is Essential For Notochord Developmentmentioning

confidence: 99%

The KH domain protein encoded by quaking functions as a dimer and is essential for notochord development inXenopus embryos

Zorn¹,

Krieg²

1997

Genes Dev.

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“…The two agents were regarded as examples of teratogens that might act indirectly on the embryo by interfering with the yolk sac-mediated histiotrophic nutrition (Lloyd and Beck 1969;Mercier-Parot and Tuchmann-Duplessis 1973;Freeman and Lloyd 1986). There are, however, a lot of experimental data showing that the teratogenic effects of the two substances can result from direct action on the embryo (Wilson et al 1959;Kaplan and Johnson 1970;Kao and Danilchik 1991;Grunz 1992;Oschwald et al 1993;Cardellini et al 1994). In the present study, suramin was administered into the coelomic cavity, facilitating direct access to the embryo.…”

Section: Teratogenic Mechanisms Of Suraminmentioning

confidence: 99%

“…Others focussed on embryonic development but only on selected morphogenic processes. Thereby, suramin was used as a tool for experimental manipulation of embryos (Kao and Danilchik 1991;Slack 1991;Grunz 1992;Oschwald et al 1993;Cardellini et al 1994), mostly with the intention of blocking the action of certain growth factors under investigation (Mitrani et al 1990;MacCabe 1993;Riese et al 1995;Yokoyama et al 1997;Cirillo et al 2001;Khot and Ghaskadbi 2001).…”

Section: Introductionmentioning

confidence: 99%

Teratogenic effects of suramin on the chick embryo

et al. 2003

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Suramin, a polysulfonated naphthylamine, has been used for the chemotherapy of trypanosomiasis and onchocerciasis since about the 1920s. Currently, it is also being tested as an anticancer agent. It is hoped that suramin might stop the progression of some kinds of cancer since it has been found to inhibit the proliferation and migration of cells and the formation of new blood vessels. These processes are not only essential for the development and progression of cancer, but also for normal embryonic development. Suramin might, therefore, be a potent teratogen. In the literature, however, we have found only scant information on this subject. In the present study, we demonstrate the teratogenic effects of suramin on chick embryos. Suramin was injected into the coelomic cavity of chick embryos on incubation day (ID) 3. Following reincubation until ID 8, suramin-treated embryos ( n=50) were examined for congenital malformations and compared with a control group ( n=30). The survival rate of suramin-treated embryos was markedly reduced compared with controls (50% vs 90%). Among the 25 survivors the following malformations were recorded: caudal dysgenesia (100%), median facial clefts with hypertelorism (92%), malformations of the aortic arch arteries (88%), hypo-/aplasia of the allantoic vesicle (84%), microphthalmia (52%), abnormalities of the great arterial trunks (44%), unilateral or bilateral cleft lips (40%), heart defects with juxtaposition of the right atrial appendage (36%), persistence of the lens vesicle (32%), median clefts of the lower beak (8%), omphalocele (4%), and cloacal exstrophy (4%). These results show that suramin is a potent teratogen. The possible implications of our findings for human beings and the possible teratogenic mechanisms of suramin are discussed. Use of suramin in experimental teratology might help to clarify the morphogenesis of median facial clefts and of some congenital heart defects.

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“…The headless defects observed as a result of Xvent-J mRNA microinjection are also seen after treatments known to ventralize embryonic mesoderm, such as suramin or LiCl treatment at the gastrula stage as well as UV irradiation before first cleavage (reviewed by Kao and Danilchik, 1991). However, no extreme dorso-anterior index (DAI) grade 0 'Bauchstuck' embryos were ever observed in Xvent-l-microinjected embryos.…”

Section: Xvent-1 Microinjection Affects Dorsal Mesoderm Developmentmentioning

confidence: 99%