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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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Wnt1-cre drives cre expression in premigratory cranial neural crest cells, while Sox10-cre is activated during cranial neural crest migration.Wnt1-cre and Sox10-cre transgenic mice were crossed to mice carrying the R26R-lacZ transgene (R26R). Embryos were harvested at various time points and stained for ß-galactosidase activity (A–C, E, G, H) or processed by whole mount in situ hybridization for Wnt1 (D) or Sox10 (F). At E8.0, Wnt1-cre expression was detectable in the anterior neural plate (A, B; arrowheads). By E8.5, robust Wnt1-cre expression (C) was apparent in the fore- and midbrain, migratory neural crest cells in the first branchial arch stream (arrowhead), and premigratory neural crest cells in the hindbrain (arc and inset). The Wnt1 expression pattern (D) for comparison, showing Wnt1 expression in cranial neural folds (arrow) and hindbrain (arc). At E8.75, Sox10-cre activity (E) was strong in the first branchial arch (asterisk), low in neural crest cells entering the first (black arrowhead) and second (white arrowhead) branchial arch streams, and undetectable in trunk premigratory and early migratory neural crest cells (dashed line), although these cells express Sox10 (F). At E9.5, Wnt1-cre (G) marked trunk neural crest cells while they were still in the neural tube (arc), while Sox10-cre (H) was not expressed in trunk neural crest cells until migration was well underway (dashed arc). Both transgenes labeled cranial neural crest cells at their destinations. e, eye; o, otic vesicle; s, somite.
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pone-0047794-g003: Wnt1-cre drives cre expression in premigratory cranial neural crest cells, while Sox10-cre is activated during cranial neural crest migration.Wnt1-cre and Sox10-cre transgenic mice were crossed to mice carrying the R26R-lacZ transgene (R26R). Embryos were harvested at various time points and stained for ß-galactosidase activity (A–C, E, G, H) or processed by whole mount in situ hybridization for Wnt1 (D) or Sox10 (F). At E8.0, Wnt1-cre expression was detectable in the anterior neural plate (A, B; arrowheads). By E8.5, robust Wnt1-cre expression (C) was apparent in the fore- and midbrain, migratory neural crest cells in the first branchial arch stream (arrowhead), and premigratory neural crest cells in the hindbrain (arc and inset). The Wnt1 expression pattern (D) for comparison, showing Wnt1 expression in cranial neural folds (arrow) and hindbrain (arc). At E8.75, Sox10-cre activity (E) was strong in the first branchial arch (asterisk), low in neural crest cells entering the first (black arrowhead) and second (white arrowhead) branchial arch streams, and undetectable in trunk premigratory and early migratory neural crest cells (dashed line), although these cells express Sox10 (F). At E9.5, Wnt1-cre (G) marked trunk neural crest cells while they were still in the neural tube (arc), while Sox10-cre (H) was not expressed in trunk neural crest cells until migration was well underway (dashed arc). Both transgenes labeled cranial neural crest cells at their destinations. e, eye; o, otic vesicle; s, somite.

Mentions: In order to compare the onset and extent of cre recombinase expression in cranial neural crest cells in Wnt1-cre and Sox10-cre lines side by side, we crossed them to the R26R cre-dependent lacZ reporter line [23]. Wnt1-cre was active as early as 3 somites (3 s), when low levels of cre expression were detectable in the anterior neural plate (Fig. 3A, arrowhead). This expression increased at 5 s (Fig. 3B, arrowhead), and by 11 s, Wnt1-cre expression was apparent in the forebrain, midbrain, and migratory neural crest cells in the first branchial arch stream (Fig. 3C, arrowhead). Premigratory neural crest cells in the hindbrain and trunk also expressed Wnt1-cre at this stage (Fig. 3C, arc; inset). The pattern of ß-galactosidase activity in Wnt1-cre embryos at 11s included the Wnt1 expression domain (Fig. 4D) plus migratory neural crest cells, in which Wnt1-cre had been expressed when these cells were in the neural folds (arrow).


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

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

Wnt1-cre drives cre expression in premigratory cranial neural crest cells, while Sox10-cre is activated during cranial neural crest migration.Wnt1-cre and Sox10-cre transgenic mice were crossed to mice carrying the R26R-lacZ transgene (R26R). Embryos were harvested at various time points and stained for ß-galactosidase activity (A–C, E, G, H) or processed by whole mount in situ hybridization for Wnt1 (D) or Sox10 (F). At E8.0, Wnt1-cre expression was detectable in the anterior neural plate (A, B; arrowheads). By E8.5, robust Wnt1-cre expression (C) was apparent in the fore- and midbrain, migratory neural crest cells in the first branchial arch stream (arrowhead), and premigratory neural crest cells in the hindbrain (arc and inset). The Wnt1 expression pattern (D) for comparison, showing Wnt1 expression in cranial neural folds (arrow) and hindbrain (arc). At E8.75, Sox10-cre activity (E) was strong in the first branchial arch (asterisk), low in neural crest cells entering the first (black arrowhead) and second (white arrowhead) branchial arch streams, and undetectable in trunk premigratory and early migratory neural crest cells (dashed line), although these cells express Sox10 (F). At E9.5, Wnt1-cre (G) marked trunk neural crest cells while they were still in the neural tube (arc), while Sox10-cre (H) was not expressed in trunk neural crest cells until migration was well underway (dashed arc). Both transgenes labeled cranial neural crest cells at their destinations. e, eye; o, otic vesicle; s, somite.
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pone-0047794-g003: Wnt1-cre drives cre expression in premigratory cranial neural crest cells, while Sox10-cre is activated during cranial neural crest migration.Wnt1-cre and Sox10-cre transgenic mice were crossed to mice carrying the R26R-lacZ transgene (R26R). Embryos were harvested at various time points and stained for ß-galactosidase activity (A–C, E, G, H) or processed by whole mount in situ hybridization for Wnt1 (D) or Sox10 (F). At E8.0, Wnt1-cre expression was detectable in the anterior neural plate (A, B; arrowheads). By E8.5, robust Wnt1-cre expression (C) was apparent in the fore- and midbrain, migratory neural crest cells in the first branchial arch stream (arrowhead), and premigratory neural crest cells in the hindbrain (arc and inset). The Wnt1 expression pattern (D) for comparison, showing Wnt1 expression in cranial neural folds (arrow) and hindbrain (arc). At E8.75, Sox10-cre activity (E) was strong in the first branchial arch (asterisk), low in neural crest cells entering the first (black arrowhead) and second (white arrowhead) branchial arch streams, and undetectable in trunk premigratory and early migratory neural crest cells (dashed line), although these cells express Sox10 (F). At E9.5, Wnt1-cre (G) marked trunk neural crest cells while they were still in the neural tube (arc), while Sox10-cre (H) was not expressed in trunk neural crest cells until migration was well underway (dashed arc). Both transgenes labeled cranial neural crest cells at their destinations. e, eye; o, otic vesicle; s, somite.
Mentions: In order to compare the onset and extent of cre recombinase expression in cranial neural crest cells in Wnt1-cre and Sox10-cre lines side by side, we crossed them to the R26R cre-dependent lacZ reporter line [23]. Wnt1-cre was active as early as 3 somites (3 s), when low levels of cre expression were detectable in the anterior neural plate (Fig. 3A, arrowhead). This expression increased at 5 s (Fig. 3B, arrowhead), and by 11 s, Wnt1-cre expression was apparent in the forebrain, midbrain, and migratory neural crest cells in the first branchial arch stream (Fig. 3C, arrowhead). Premigratory neural crest cells in the hindbrain and trunk also expressed Wnt1-cre at this stage (Fig. 3C, arc; inset). The pattern of ß-galactosidase activity in Wnt1-cre embryos at 11s included the Wnt1 expression domain (Fig. 4D) plus migratory neural crest cells, in which Wnt1-cre had been expressed when these cells were in the neural folds (arrow).

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