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Requirement of the juxtamembrane domain of the cadherin cytoplasmic tail for morphogenetic cell rearrangement during myotome development.

Horikawa K, Takeichi M - J. Cell Biol. (2001)

Bottom Line: However, a triple alanine substitution in the JM domain, which specifically inhibited the p120ctn binding, had no effect on myotome development.Furthermore, a dominant negative N-cadherin, which had a deletion at the extracellular domain but maintained the normal cytoplasmic tail, did not affect myotome expansion; although it disrupted intersomite boundaries.Overexpression of p120ctn also did not affect myotome expansion, but it did perturb myofiber orientation.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.

ABSTRACT
During development, the activity of cadherin cell adhesion molecules is assumed to be regulated to allow for cell rearrangement or translocation. Previous studies suggest that the juxtamembrane (JM) domain of the cadherin cytoplasmic tail, which contains the site for binding to p120ctn, has a regulatory function in this adhesion system. To study the possible role of JM domain-dependent cadherin regulation in embryonic cell rearrangement, we ectopically expressed a series of N-cadherin mutants in developing somites of chicken embryos. When a JM domain-deficient N-cadherin was expressed, the morphogenetic expansion of the myotome was strongly suppressed. However, a triple alanine substitution in the JM domain, which specifically inhibited the p120ctn binding, had no effect on myotome development. Furthermore, a dominant negative N-cadherin, which had a deletion at the extracellular domain but maintained the normal cytoplasmic tail, did not affect myotome expansion; although it disrupted intersomite boundaries. Overexpression of p120ctn also did not affect myotome expansion, but it did perturb myofiber orientation. These and other observations suggest that the JM domain of N-cadherin has a regulatory role in myotome cell rearrangement in which molecules other than p120ctn are involved. The p120ctn molecule itself seems to play a critical role in the arrangement of myofibers.

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Observations on the developmental effect of the JM(−) cadherin expression. Embryos were injected with AdV-Ncad (A–D) or AdV-cN/JM(−) (E–H) and double stained for the cadherin-attached tag (green) and β-catenin (red) at 12, 24, 36, and 48 h after the injection. Expression of the JM(−) cadherin did not affect the organization of epithelial somites (E). However, the expansion of the myotome along the DV axis was inhibited from the beginning of this process. Bar, 250 μm.
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fig3: Observations on the developmental effect of the JM(−) cadherin expression. Embryos were injected with AdV-Ncad (A–D) or AdV-cN/JM(−) (E–H) and double stained for the cadherin-attached tag (green) and β-catenin (red) at 12, 24, 36, and 48 h after the injection. Expression of the JM(−) cadherin did not affect the organization of epithelial somites (E). However, the expansion of the myotome along the DV axis was inhibited from the beginning of this process. Bar, 250 μm.

Mentions: Next, we observed different stages of development to determine when the abnormal somite morphogenesis began in AdV-cN/JM(−)–injected embryos. As seen in Fig. 3, E–H, at the epithelial stage somites expressing the JM domain–deficient (JM[−]) cadherin appeared to be normal, whereas as soon as myotome differentiation began its DV expansion was retarded. To further analyze the abnormal patterning of myotome in AdV-cN/JM(−)–injected embryos, we coinjected the AdV-cN/JM(−) with a relatively low titer of AdV-lacZ. This procedure allowed us to label selectively a subpopulation of myotome cells with LacZ that enter into the postmitotic phase at earlier developmental stages, since this marker is diluted considerably in cells which continue to proliferate until later stages. In embryos expressing the normal N-cadherin, most LacZ-positive cells were localized adjacent to the dermatome (Fig. 4 A), following the normal sequence of myotome cell translocation (Denetclaw et al., 1997; Kahane et al., 1998; Denetclaw and Ordahl, 2000). However, in AdV-cN/JM(−)–injected embryos, LacZ-positive cells accumulated at a deeper position within the myotome cluster with LacZ-negative cells localizing at the surface side (Fig. 4 B). Thus, the ordered myotomal cell colonization pattern was reversed in AdV-cN/JM(−)–injected embryos as summarized in Fig. 4 C, indicating that the effect of AdV-cN/JM(−) expression involved a disturbance of cell positioning.


Requirement of the juxtamembrane domain of the cadherin cytoplasmic tail for morphogenetic cell rearrangement during myotome development.

Horikawa K, Takeichi M - J. Cell Biol. (2001)

Observations on the developmental effect of the JM(−) cadherin expression. Embryos were injected with AdV-Ncad (A–D) or AdV-cN/JM(−) (E–H) and double stained for the cadherin-attached tag (green) and β-catenin (red) at 12, 24, 36, and 48 h after the injection. Expression of the JM(−) cadherin did not affect the organization of epithelial somites (E). However, the expansion of the myotome along the DV axis was inhibited from the beginning of this process. Bar, 250 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199319&req=5

fig3: Observations on the developmental effect of the JM(−) cadherin expression. Embryos were injected with AdV-Ncad (A–D) or AdV-cN/JM(−) (E–H) and double stained for the cadherin-attached tag (green) and β-catenin (red) at 12, 24, 36, and 48 h after the injection. Expression of the JM(−) cadherin did not affect the organization of epithelial somites (E). However, the expansion of the myotome along the DV axis was inhibited from the beginning of this process. Bar, 250 μm.
Mentions: Next, we observed different stages of development to determine when the abnormal somite morphogenesis began in AdV-cN/JM(−)–injected embryos. As seen in Fig. 3, E–H, at the epithelial stage somites expressing the JM domain–deficient (JM[−]) cadherin appeared to be normal, whereas as soon as myotome differentiation began its DV expansion was retarded. To further analyze the abnormal patterning of myotome in AdV-cN/JM(−)–injected embryos, we coinjected the AdV-cN/JM(−) with a relatively low titer of AdV-lacZ. This procedure allowed us to label selectively a subpopulation of myotome cells with LacZ that enter into the postmitotic phase at earlier developmental stages, since this marker is diluted considerably in cells which continue to proliferate until later stages. In embryos expressing the normal N-cadherin, most LacZ-positive cells were localized adjacent to the dermatome (Fig. 4 A), following the normal sequence of myotome cell translocation (Denetclaw et al., 1997; Kahane et al., 1998; Denetclaw and Ordahl, 2000). However, in AdV-cN/JM(−)–injected embryos, LacZ-positive cells accumulated at a deeper position within the myotome cluster with LacZ-negative cells localizing at the surface side (Fig. 4 B). Thus, the ordered myotomal cell colonization pattern was reversed in AdV-cN/JM(−)–injected embryos as summarized in Fig. 4 C, indicating that the effect of AdV-cN/JM(−) expression involved a disturbance of cell positioning.

Bottom Line: However, a triple alanine substitution in the JM domain, which specifically inhibited the p120ctn binding, had no effect on myotome development.Furthermore, a dominant negative N-cadherin, which had a deletion at the extracellular domain but maintained the normal cytoplasmic tail, did not affect myotome expansion; although it disrupted intersomite boundaries.Overexpression of p120ctn also did not affect myotome expansion, but it did perturb myofiber orientation.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.

ABSTRACT
During development, the activity of cadherin cell adhesion molecules is assumed to be regulated to allow for cell rearrangement or translocation. Previous studies suggest that the juxtamembrane (JM) domain of the cadherin cytoplasmic tail, which contains the site for binding to p120ctn, has a regulatory function in this adhesion system. To study the possible role of JM domain-dependent cadherin regulation in embryonic cell rearrangement, we ectopically expressed a series of N-cadherin mutants in developing somites of chicken embryos. When a JM domain-deficient N-cadherin was expressed, the morphogenetic expansion of the myotome was strongly suppressed. However, a triple alanine substitution in the JM domain, which specifically inhibited the p120ctn binding, had no effect on myotome development. Furthermore, a dominant negative N-cadherin, which had a deletion at the extracellular domain but maintained the normal cytoplasmic tail, did not affect myotome expansion; although it disrupted intersomite boundaries. Overexpression of p120ctn also did not affect myotome expansion, but it did perturb myofiber orientation. These and other observations suggest that the JM domain of N-cadherin has a regulatory role in myotome cell rearrangement in which molecules other than p120ctn are involved. The p120ctn molecule itself seems to play a critical role in the arrangement of myofibers.

Show MeSH
Related in: MedlinePlus