Related Experiment Video
Updated: Aug 25, 2026
Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo
Published on: February 2, 2016
Xenopus MBD3 plays a crucial role in an early stage of development
Hidetomo Iwano1, Masahiko Nakamura, Shoji Tajima
1Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan.
Abstract:
DNA methylation plays a crucial role in gene silencing via recruitment of the proteins that specifically recognize methyl-CpG. In the present study, we have shown that two splicing isoforms of MBD3, xMBD3 and xMBD3LF, are the major methyl-CpG binding proteins in Xenopus eggs and early stage embryos. They were highly expressed in the eyes and central nerve system of tadpoles. Inhibition of the expression of xMBD3 by antisense oligonucleotides severely affected embryogenesis. Low-dose injection of antisense oligonucleotides specifically affected eye formation. An identical phenotype was observed on the forced expression of xMBD3 mutated in the methyl-CpG binding domain (MBD) and xMBD3LF, those of which lack methylated DNA binding activity. On the other hand, the eye-defective phenotype was not induced on the injection of truncated forms of mutant xMBD3 or xMBD3LF that contained MBD. We propose that MBD3, distinct from the case in mouse, plays a crucial role in the recognition of methylated genes as an intrinsic component of the complex to guide the corepressor complex during an early stage of Xenopus embryogenesis.
Insights
Methyl-CpG binding domain protein 3 (MBD3) isoforms are key in Xenopus development. Their function in gene silencing is critical for embryogenesis, particularly eye formation, distinct from mouse MBD3 roles.
Area of Science:
- Developmental Biology
- Epigenetics
- Molecular Biology
Background:
- DNA methylation is vital for gene silencing through methyl-CpG recognition proteins.
- MBD3 proteins are implicated in gene regulation, but their specific roles in early vertebrate development are not fully understood.
Purpose of the Study:
- To investigate the function of MBD3 splicing isoforms in Xenopus embryogenesis.
- To determine the role of methyl-CpG binding activity in MBD3's developmental function.
Main Methods:
- Identified and characterized MBD3 isoforms (xMBD3, xMBD3LF) in Xenopus.
- Utilized antisense oligonucleotides to inhibit xMBD3 expression.
- Injected mutated MBD3 constructs lacking methyl-CpG binding activity.
Main Results:
- xMBD3 and xMBD3LF are major methyl-CpG binding proteins in Xenopus embryos, highly expressed in the eye and central nervous system.
- Inhibition of xMBD3 severely impaired embryogenesis, with low doses specifically affecting eye formation.
- Mutant xMBD3 and xMBD3LF lacking methyl-CpG binding activity phenocopied the eye defect, while truncated forms with intact binding domains did not.
Conclusions:
- Xenopus MBD3 plays a critical role in early embryogenesis, particularly eye development, through a mechanism potentially independent of direct methylated DNA binding.
- Unlike in mice, Xenopus MBD3 appears to function as an intrinsic component guiding corepressor complexes in methylated gene recognition during early development.
