Analysis of Cell Fate Commitment in <i>Xenopus</i> Embryos

Moody, Sally A.

doi:10.1101/pdb.top097246

Cited by 3 publications

(4 citation statements)

References 34 publications

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“…To distinguish between whether this rescue effect of HCN2 on non‐CNS organs results from its expression in the organs themselves, or from distant tissues, we then injected Hcn2‐WT mRNA into precursors of mostly neural (distant) tissue (dorsal blastomeres 86,87 ) or mostly ventral (local) tissues (ventral blastomeres 86,87 ) at four‐cell stage. While the four‐cell stage fate map is not exclusively neural vs. non‐CNS, it does enable reliable targeting of mRNA to, or away from, specific organs based on their tissue origin 88–91 .…”

Section: Resultsmentioning

confidence: 99%

“…To distinguish between whether this effect of HCN2 on ethanolinduced brain and eye defects can be exerted from local (neural) or distant (ventral) tissues, we then injected Hcn2-WT mRNA into precursors of mostly neural (local) tissue (dorsal blastomeres 86,87 ) or mostly non-CNS (distant) tissues (ventral blastomeres 86,87 ) at four-cell stage. The embryos were then exposed to ethanol (2%, stage 9-40).…”

Section: Ethanol Exposure-induced Brain and Eye Defects Are Rescued B...mentioning

confidence: 99%

“…To distinguish between whether this rescue/protection effect on heart and gut development by HCN2 is local (ventral/non-CNS) or can be achieved by distant (neural) tissues, the Notch ICD-injected embryos were injected with Hcn2-WT mRNA into precursors of mostly neural (distant) tissue (dorsal blastomeres 86,87 ) or mostly non-CNS (local) tissues (ventral blastomeres 86,87 ) at four-cell stage. Large scale morphology of heart and gut was evaluated at stage 45 (Figure 9D,E).…”

Section: Overactive Notch (Icd)-induced Heart and Gut Morphology Defe...mentioning

confidence: 99%

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HCN2 channel‐induced rescue of brain, eye, heart and gut teratogenesis caused by nicotine, ethanol and aberrant notch signalling

Pai

Levin

2022

Wound Repair Regeneration

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Organogenesis is a complex process that can be disrupted by embryonic exposure to teratogens or mutation-induced alterations in signalling pathways, both of which result in organ mispatterning. Building on prior work in Xenopus laevis that showed that increased HCN2 ion channel activity rescues nicotine-induced brain and eye morphogenesis, we demonstrate much broader HCN2-based rescue of organ patterning defects. Induced HCN2 expression in both local or distant tissues can rescue CNS (brain and eye) as well as non-CNS (heart and gut) organ defects induced by three different teratogenic conditions: nicotine exposure, ethanol exposure or aberrant Notch protein. Rescue can also be induced by small-molecule HCN2 channel activators, even with delayed treatment initiation. Our results suggest that HCN2 (likely mediated by bioelectric signals) can be an effective regulator of organogenesis from all three germ layers (ectoderm, mesoderm and endoderm) and reveal non-cellautonomous influences on organ formation that work at a considerable distance during embryonic development. These results suggest molecular bioelectric strategies for repair that could be explored in the future for regenerative medicine.

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Section: Resultsmentioning

confidence: 99%

Section: Ethanol Exposure-induced Brain and Eye Defects Are Rescued B...mentioning

confidence: 99%

Section: Overactive Notch (Icd)-induced Heart and Gut Morphology Defe...mentioning

confidence: 99%

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HCN2 channel‐induced rescue of brain, eye, heart and gut teratogenesis caused by nicotine, ethanol and aberrant notch signalling

Pai

Levin

2022

Wound Repair Regeneration

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“…This allows us to monitor changes in development in real time and is ideal for biochemical analyses. In addition, cell fates have been mapped to early cleavage stage embryos ( Moody, 1987 ; Moody, 2019 ), thus allowing targeted injection of reagents into defined regions to specifically affect gene levels in tissue-specific manners. Importantly, tools to modify levels of gene expression are titratable and thus we can avoid the lethality of gene knockout, which occur in mouse models ( Eisen and Smith, 2008 ).…”

Section: Discussionmentioning

confidence: 99%

Recognition of H2AK119ub plays an important role in RSF1-regulated early Xenopus development

Parast,

Yu,

Chen

et al. 2023

Front. Cell Dev. Biol.

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Polycomb group (PcG) proteins are key regulators of gene expression and developmental programs via covalent modification of histones, but the factors that interpret histone modification marks to regulate embryogenesis are less studied. We previously identified Remodeling and Spacing Factor 1 (RSF1) as a reader of histone H2A lysine 119 ubiquitination (H2AK119ub), the histone mark deposited by Polycomb Repressive Complex 1 (PRC1). In the current study, we used Xenopus laevis as a model to investigate how RSF1 affects early embryonic development and whether recognition of H2AK119ub is important for the function of RSF1. We showed that knockdown of Xenopus RSF1, rsf1, not only induced gastrulation defects as reported previously, but specific targeted knockdown in prospective neural precursors induced neural and neural crest defects, with reductions of marker genes. In addition, similar to knockdown of PRC1 components in Xenopus, the anterior-posterior neural patterning was affected in rsf1 knockdown embryos. Binding of H2AK119ub appeared to be crucial for rsf1 function, as a construct with deletion of the UAB domain, which is required for RSF1 to recognize the H2AK119ub nucleosomes, failed to rescue rsf1 morphant embryos and was less effective in interfering with early Xenopus development when ectopically expressed. Furthermore, ectopic deposition of H2AK119ub on the Smad2 target gene gsc using a ring1a-smad2 fusion protein led to ectopic recruitment of RSF1. The fusion protein was inefficient in inducing mesodermal markers in the animal region or a secondary axis when expressed in the ventral tissues. Taken together, our results reveal that rsf1 modulates similar developmental processes in early Xenopus embryos as components of PRC1 do, and that RSF1 acts at least partially through binding to the H2AK119ub mark via the UAB domain during development.

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Xenopus as an Experimental Organism

Tadjuidje

2022

Encyclopedia of Life Sciences

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The South African clawed frog, Xenopus laevis , is a popular model system to study development. It is easy to maintain a breeding frog colony, females can be spawned all year round and hundreds of synchronously growing embryos can be generated from a single fertilisation. Embryos are easily amenable to microsurgery at any stage of development and adults survive surgeries performed under limited aseptic conditions. The ease of injecting oligonucleotides or messenger ribonucleic acid (mRNA) into Xenopus leavis embryos has contributed to the discovery of genes with key functions in development. Another singularity of Xenopus leavis is the ease to manipulate its oocytes before fertilisation; this has been a powerful tool to identify the function of maternally deposited mRNAs in development. Over the past two decades, transgenic strategies have been developed using the related species Xenopus tropicalis and this is broadening the contribution of Xenopus to the understanding of early development. Key Concepts Xenopus laevis is easy to raise and feed in large colonies in the lab, and commercial vendors can now supply frogs and embryos at all developmental stages for research. The female Xenopus can be induced to spawn repeatedly at any season, making it possible to obtain embryos all year round. Xenopus leavis' eggs are large, they measure around 1.3 mm in diameter and are usually laid in large numbers that are fertilised in vitro . The Xenopus embryos develop outside the female, its early development is very fast, making it possible to study a full developmental program in about 3 days, with the possibility to manipulate the embryos at any stage of development. Xenopus leavis oocytes can easily be obtained and manipulated before fertilisation, making it possible to study the function of maternally deposited mRNAs. The mechanisms of tissue and body axis formation have been elucidated from research carried out in Xenopus leavis embryos, and a Xenopus toxicological test called FETAX has been recommended by scientists from the American Food and Drug Administration, for the teratogenic screening of new drugs candidates. Gene editing techniques have been developed for Xenopus, making it an excellent model to mimic human mutations and study human diseases like cancers and congenital diseases. The sequencing of the diploid genome, ease of obtaining and injecting large numbers of eggs and the relatively short lifespan makes Xenopus tropicalis a very powerful model for gene editing and transgenic studies of organogenesis. Eggs of Xenopus leavis provide a model of choice for studying the regulation of the cell cycle. A database called Xenbase is now available to the Xenopus research community; it contains usefully and regularly updated information on Xenopus research and resources.

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Analysis of Cell Fate Commitment in Xenopus Embryos

Cited by 3 publications

References 34 publications

HCN2 channel‐induced rescue of brain, eye, heart and gut teratogenesis caused by nicotine, ethanol and aberrant notch signalling

HCN2 channel‐induced rescue of brain, eye, heart and gut teratogenesis caused by nicotine, ethanol and aberrant notch signalling

Recognition of H2AK119ub plays an important role in RSF1-regulated early Xenopus development

Xenopus as an Experimental Organism

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