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DNA methyltransferase 3b is dispensable for mouse neural crest development.

Jacques-Fricke BT, Roffers-Agarwal J, Gammill LS - PLoS ONE (2012)

Bottom Line: In both neural crest-specific and fully DNMT3b-mutant embryos, cranial neural crest cells exhibited only subtle migration defects, with increased numbers of dispersed cells trailing organized streams in the head.In spite of this, the resulting cranial ganglia, craniofacial skeleton, and heart developed normally when neural crest cells lacked DNMT3b.We conclude that defects in neural crest derivatives in DNMT3b mutant mice reflect a requirement for DNMT3b in lineages such as the branchial arch mesendoderm or the cardiac mesoderm that interact with neural crest cells during formation of these structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America.

ABSTRACT
The neural crest is a population of multipotent cells that migrates extensively throughout vertebrate embryos to form diverse structures. Mice mutant for the de novo DNA methyltransferase DNMT3b exhibit defects in two neural crest derivatives, the craniofacial skeleton and cardiac ventricular septum, suggesting that DNMT3b activity is necessary for neural crest development. Nevertheless, the requirement for DNMT3b specifically in neural crest cells, as opposed to interacting cell types, has not been determined. Using a conditional DNMT3b allele crossed to the neural crest cre drivers Wnt1-cre and Sox10-cre, neural crest DNMT3b mutants were generated. In both neural crest-specific and fully DNMT3b-mutant embryos, cranial neural crest cells exhibited only subtle migration defects, with increased numbers of dispersed cells trailing organized streams in the head. In spite of this, the resulting cranial ganglia, craniofacial skeleton, and heart developed normally when neural crest cells lacked DNMT3b. This indicates that DNTM3b is not necessary in cranial neural crest cells for their development. We conclude that defects in neural crest derivatives in DNMT3b mutant mice reflect a requirement for DNMT3b in lineages such as the branchial arch mesendoderm or the cardiac mesoderm that interact with neural crest cells during formation of these structures.

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Craniofacial development is normal in neural crest-specific DNMT3b mutants.Skeletal preparations of E16.5 embryos from DNMT3b+/fl (wildtype; A, n = 12) and either Sox10-cre; DNMT3bfl/− (B, n = 5) or Wnt1-cre; DNMT3bfl/− (homozygous deleted in neural crest cells; C, n = 7) were alizarin red and alcian blue stained. (A–C) Lateral view; (D–G) skull vault; (D’–G’) skull base, with an inset of the mandible. No defects were apparent in the development, size or placement of cranial skeletal elements. AL, alisphenoid; BO, basioccipital; BS, basisphenoid; EO, exoccipital; Fr, frontal; IP, interparietal; Md, mandible; P, parietal; PT, palatine; Ty, tympanic.
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pone-0047794-g006: Craniofacial development is normal in neural crest-specific DNMT3b mutants.Skeletal preparations of E16.5 embryos from DNMT3b+/fl (wildtype; A, n = 12) and either Sox10-cre; DNMT3bfl/− (B, n = 5) or Wnt1-cre; DNMT3bfl/− (homozygous deleted in neural crest cells; C, n = 7) were alizarin red and alcian blue stained. (A–C) Lateral view; (D–G) skull vault; (D’–G’) skull base, with an inset of the mandible. No defects were apparent in the development, size or placement of cranial skeletal elements. AL, alisphenoid; BO, basioccipital; BS, basisphenoid; EO, exoccipital; Fr, frontal; IP, interparietal; Md, mandible; P, parietal; PT, palatine; Ty, tympanic.

Mentions: Likewise, neural crest deletion of DNMT3b did not affect craniofacial development. DNMT3b−/− mice die before craniofacial structures form, however, mice with missense mutations equivalent to those in patients with ICF syndrome exhibit delayed skull vault ossification, and shorter, wider frontal bones [16]. To determine if these DNMT3b-dependent abnormalities reflect an essential role for DNMT3b in neural crest cells during craniofacial development, we alizarin red and alcian blue stained skeletal preps of E16.5 mouse embryos. Regardless of genotype, the size, shape, and developmental progress of cranial bones was normal. In a lateral view, all cranial skeletal elements were apparent and exhibited the appropriate length and pattern in wildtype (Fig. 6A) compared to neural crest mutant animals (Fig. 6B, C). Indeed when the skull vault was examined, the frontal, parietal, and interparietal bones were a similar length and width, and ossification was proceeding normally in all embryos (Fig. 6D–G). When viewed from the skull base, the size, shape and position of cranial elements was comparable in control (Fig. 6D’, F’) and neural crest DNMT3b mutants (Fig. 6E’, G’), and the mandibles were indistinguishable (insets). Altogether, these data show that DNMT3b is not necessary in neural crest cells for the formation of neural crest derived structures.


DNA methyltransferase 3b is dispensable for mouse neural crest development.

Jacques-Fricke BT, Roffers-Agarwal J, Gammill LS - PLoS ONE (2012)

Craniofacial development is normal in neural crest-specific DNMT3b mutants.Skeletal preparations of E16.5 embryos from DNMT3b+/fl (wildtype; A, n = 12) and either Sox10-cre; DNMT3bfl/− (B, n = 5) or Wnt1-cre; DNMT3bfl/− (homozygous deleted in neural crest cells; C, n = 7) were alizarin red and alcian blue stained. (A–C) Lateral view; (D–G) skull vault; (D’–G’) skull base, with an inset of the mandible. No defects were apparent in the development, size or placement of cranial skeletal elements. AL, alisphenoid; BO, basioccipital; BS, basisphenoid; EO, exoccipital; Fr, frontal; IP, interparietal; Md, mandible; P, parietal; PT, palatine; Ty, tympanic.
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pone-0047794-g006: Craniofacial development is normal in neural crest-specific DNMT3b mutants.Skeletal preparations of E16.5 embryos from DNMT3b+/fl (wildtype; A, n = 12) and either Sox10-cre; DNMT3bfl/− (B, n = 5) or Wnt1-cre; DNMT3bfl/− (homozygous deleted in neural crest cells; C, n = 7) were alizarin red and alcian blue stained. (A–C) Lateral view; (D–G) skull vault; (D’–G’) skull base, with an inset of the mandible. No defects were apparent in the development, size or placement of cranial skeletal elements. AL, alisphenoid; BO, basioccipital; BS, basisphenoid; EO, exoccipital; Fr, frontal; IP, interparietal; Md, mandible; P, parietal; PT, palatine; Ty, tympanic.
Mentions: Likewise, neural crest deletion of DNMT3b did not affect craniofacial development. DNMT3b−/− mice die before craniofacial structures form, however, mice with missense mutations equivalent to those in patients with ICF syndrome exhibit delayed skull vault ossification, and shorter, wider frontal bones [16]. To determine if these DNMT3b-dependent abnormalities reflect an essential role for DNMT3b in neural crest cells during craniofacial development, we alizarin red and alcian blue stained skeletal preps of E16.5 mouse embryos. Regardless of genotype, the size, shape, and developmental progress of cranial bones was normal. In a lateral view, all cranial skeletal elements were apparent and exhibited the appropriate length and pattern in wildtype (Fig. 6A) compared to neural crest mutant animals (Fig. 6B, C). Indeed when the skull vault was examined, the frontal, parietal, and interparietal bones were a similar length and width, and ossification was proceeding normally in all embryos (Fig. 6D–G). When viewed from the skull base, the size, shape and position of cranial elements was comparable in control (Fig. 6D’, F’) and neural crest DNMT3b mutants (Fig. 6E’, G’), and the mandibles were indistinguishable (insets). Altogether, these data show that DNMT3b is not necessary in neural crest cells for the formation of neural crest derived structures.

Bottom Line: In both neural crest-specific and fully DNMT3b-mutant embryos, cranial neural crest cells exhibited only subtle migration defects, with increased numbers of dispersed cells trailing organized streams in the head.In spite of this, the resulting cranial ganglia, craniofacial skeleton, and heart developed normally when neural crest cells lacked DNMT3b.We conclude that defects in neural crest derivatives in DNMT3b mutant mice reflect a requirement for DNMT3b in lineages such as the branchial arch mesendoderm or the cardiac mesoderm that interact with neural crest cells during formation of these structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America.

ABSTRACT
The neural crest is a population of multipotent cells that migrates extensively throughout vertebrate embryos to form diverse structures. Mice mutant for the de novo DNA methyltransferase DNMT3b exhibit defects in two neural crest derivatives, the craniofacial skeleton and cardiac ventricular septum, suggesting that DNMT3b activity is necessary for neural crest development. Nevertheless, the requirement for DNMT3b specifically in neural crest cells, as opposed to interacting cell types, has not been determined. Using a conditional DNMT3b allele crossed to the neural crest cre drivers Wnt1-cre and Sox10-cre, neural crest DNMT3b mutants were generated. In both neural crest-specific and fully DNMT3b-mutant embryos, cranial neural crest cells exhibited only subtle migration defects, with increased numbers of dispersed cells trailing organized streams in the head. In spite of this, the resulting cranial ganglia, craniofacial skeleton, and heart developed normally when neural crest cells lacked DNMT3b. This indicates that DNTM3b is not necessary in cranial neural crest cells for their development. We conclude that defects in neural crest derivatives in DNMT3b mutant mice reflect a requirement for DNMT3b in lineages such as the branchial arch mesendoderm or the cardiac mesoderm that interact with neural crest cells during formation of these structures.

Show MeSH
Related in: MedlinePlus