The mode of action of lithium salts in amphibian development

Hall, Thomas S.

doi:10.1002/jez.1400890102

Cited by 38 publications

(11 citation statements)

References 41 publications

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“…After the mid-blastula transition, exposure to lithium or Xwnt-8 has a markedly different effect on the body pattern, producing a loss of structures anterior to the hindbrain (Yamaguchi and Shinagawa 1989}, causing a transformation of presumptive notochord into somite tissue (Lehmann 1937;Cohen 1938;B~ickstr6m 1954) and inducing mesodermal differentiations in ectoderm (Masui 1961). As with Xwnt-8, the primary target in lithium-induced microcephaly has been shown to be the head mesoderm, rather than the neuroctoderm (Hall 1942). Although the molecular mechanism by which the Xwnt-8 signal is transduced is unknown, the effects of lithium in Xenopus are believed to be mediated by an inhibition of the polyphosphoinositide cycle (Busa and Gimlich 1989;Maslanski et al 1992).…”

Section: Genes and Developmentmentioning

confidence: 99%

Interactions between Xwnt-8 and Spemann organizer signaling pathways generate dorsoventral pattern in the embryonic mesoderm of Xenopus.

Christian¹,

Moon²

1993

Genes Dev.

425

292

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This study analyzes the hierarchy of signals that spatially restrict expression of Xenopus Xwnt-8 to mesodermal cells outside of the Spemann organizer field and examines the potential role that endogenous Xwnt-8 may play in dorsoventral patterning of the embryonic mesoderm. The effects of ectopic introduction of a Nieuwkoop center-like activity or of ectopic expression of goosecoid, on the distribution of endogenous Xwnt-8 transcripts were analyzed. The results of these studies are consistent with the hypothesis that maternally derived signals from the Nieuwkoop center function to positively regulate expression of the homeo box gene goosecoid in Spemann organizer cells, leading to a subsequent repression of Xwnt-8 expression in these cells. This exclusion of Xwnt-8 from cells of the organizer field may be important for normal dorsal development, in that ectopic expression of Xwnt-8 in organizer cells after the midblastula stage, by injection of plasmid DNA, ventralizes the fate of these cells. This is distinct from the previously observed dorsalizing effect of Xwnt-8 when expressed prior to the midblastula stage by injection of RNA. The effects of plasmid-derived Xwnt-8 on isolated blastula animal cap ectoderm were also analyzed. Expression of Xwnt-8 in animal pole ectoderm after the midblastula stage ventralizes the response of dorsal animal pole cells to activin and allows naive ectodermal cells to differentiate as ventral mesoderm in the absence of added growth factors. Collectively, these data are consistent with the hypothesis that Xwnt-8 plays a role in the mesodermal differentiation of ventral marginal zone cells during normal development. Furthermore, endogenous Xwnt-8 may ventralize the response of lateral mesodermal cells to dorsalizing signals from the organizer, thus contributing to the graded nature of the final body pattern.

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Section: Genes and Developmentmentioning

confidence: 99%

Interactions between Xwnt-8 and Spemann organizer signaling pathways generate dorsoventral pattern in the embryonic mesoderm of Xenopus.

Christian¹,

Moon²

1993

Genes Dev.

425

292

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“…Lithium seems to interfere with the inositol second messenger pathway, presumably functioning in ventral mesoderm induction (Busa and Gimlich, 1989). Embryos are also sensitive to lithium after MBT, but then the effect is to prevent notochord development and reduce anterior structures (Hall, 1942;Yamaguchi and Shinagawa, 1989). It is assumed that some process is affected that is different from that pre-MBT, and it is not concerned with axis specification, but rather the differentiation of specific tissue types.…”

Section: Introductionmentioning

confidence: 96%

N-acetyl-cysteine causes a late re-specification of the anteroposterior axis in theXenopus embryo

Gatherer

Woodland

1996

Dev. Dyn.

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“…Studies have shown that exposure of embryos to lithium at an early stage (cleavage stage) usually results in reduction of posterior structures, such as the tail fin and segmented somites in the larval stage (1,4,6,7,15,26). On the contrary, exposure to lithium at a later stage (gastrula stage) results in reduction of anterior structures, such as the head, optic vesicles and the cement gland (1,11,17,21,22). These findings imply that the effect of lithium on formation of the larval body pattern changes during the blastula to gastrula stage.…”

Section: Introductionmentioning

confidence: 98%

Marked Alteration at Midblastula Transition in the Effect of Lithium on Formation of the Larval Body Pattern of Xenopus laevis

Yamaguchi

Shinagawa

1989

Dev Growth Differ

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Embryos of Xenopus laevis were exposed to 0.4 M LiCl for 5 min at various stages of development. The effect of lithium on the larval body pattern could be detected from the 2-cell to the late gastrula stage, but changed from reduction of posterior structures ("anteriorization") to reduction of anterior structures ("posteriorization") just after the 12th cleavage, the time of midblastula transition (MET). Temporal coincidence of MBT with alteration of the effect of lithium was observed even with embryos derived from half-egg fragment, in which MET occurs just after the 11 th cleavage. These results suggest the existence of a mechanism for formation of the basic plan of the larval body whose function changes at MBT. Combinations of the pre-and post-MBT exposures to lithium induced marked posteriorization in most larvae, indicating that the basic plan is not irreversibly determined until MBT, but is fixed during post-MBT stages.

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The mode of action of lithium salts in amphibian development

Cited by 38 publications

References 41 publications

Interactions between Xwnt-8 and Spemann organizer signaling pathways generate dorsoventral pattern in the embryonic mesoderm of Xenopus.

Interactions between Xwnt-8 and Spemann organizer signaling pathways generate dorsoventral pattern in the embryonic mesoderm of Xenopus.

N-acetyl-cysteine causes a late re-specification of the anteroposterior axis in theXenopus embryo

Marked Alteration at Midblastula Transition in the Effect of Lithium on Formation of the Larval Body Pattern of Xenopus laevis

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