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Itm2a expression in the developing mouse first lower molar, and the subcellular localization of Itm2a in mouse dental epithelial cells.

Kihara M, Kiyoshima T, Nagata K, Wada H, Fujiwara H, Hasegawa K, Someya H, Takahashi I, Sakai H - PLoS ONE (2014)

Bottom Line: A tiny amount of Itm2a was colocalized with lysosomes and endoplasmic reticulum.Minimal or no overlap between the Itm2a-EGFP signals with the other organelle markers for endoplasmic reticulum, lysosome and mitochondria used in this study noted in the cytoplasm.These findings suggest that Itm2a may play a role in cell differentiation during odontogenesis, rather than during the initiation of tooth germ formation, and may be related to the targeting of proteins associated with enamel and dentin matrices in the secretory pathway.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Oral Pathology, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan; Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.

ABSTRACT
Itm2a is a type II transmembrane protein with a BRICHOS domain. We investigated the temporospatial mRNA and protein expression patterns of Itm2a in the developing lower first molar, and examined the subcellular localization of Itm2a in murine dental epithelial (mDE6) cells. From the initiation to the bud stage, the in situ and protein signals of Itm2a were not detected in either the dental epithelial or mesenchymal cells surrounding the tooth bud. However, at the bell stage, these signals of Itm2a were primarily observed in the inner enamel epithelium of the enamel organ. After the initiation of the matrix formation, strong signals were detected in ameloblasts and odontoblasts. Itm2a showed a punctate pattern in the cytoplasm of the mDE6 cells. The perinuclear-localized Itm2a displayed a frequent overlap with the Golgi apparatus marker, GM130. A tiny amount of Itm2a was colocalized with lysosomes and endoplasmic reticulum. Minimal or no overlap between the Itm2a-EGFP signals with the other organelle markers for endoplasmic reticulum, lysosome and mitochondria used in this study noted in the cytoplasm. These findings suggest that Itm2a may play a role in cell differentiation during odontogenesis, rather than during the initiation of tooth germ formation, and may be related to the targeting of proteins associated with enamel and dentin matrices in the secretory pathway.

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The in situ expression of Itm2a mRNA in the developing tooth germ at the late bell stage.A. On PN0, the in situ expression of Itm2a was detected in the inner enamel epithelial cells (black arrow). B. The boxed area in A is shown at a higher magnification. The in situ expression of Itm2a was detected in the inner enamel epithelial cells (black arrow) and odontoblasts (white arrowhead). C. An HE-stained section of the tooth germ on PN1 is shown, corresponding to the region shown in B. D. On PN1, the initiation stage of matrix formation, in situ Itm2a signals were observed in the ameloblasts (white arrow) and odontoblasts (white arrowheads). E & G. The red- and blue-boxed areas in D are shown at a higher magnification, respectively. The in situ expression of Itm2a was detected in the ameloblasts (white arrow) and odontoblasts (white arrowheads). An in situ Itm2a signal was also observed in preameloblasts (blue arrow). F & H. HE-stained sections of the tooth germ on PN1 are shown, corresponding to the regions shown in E and G, respectively. Li; lingual side, Bu; buccal side. Scale bars; 200 µm (A, D), 100 µm (B, C, E–H).
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pone-0103928-g002: The in situ expression of Itm2a mRNA in the developing tooth germ at the late bell stage.A. On PN0, the in situ expression of Itm2a was detected in the inner enamel epithelial cells (black arrow). B. The boxed area in A is shown at a higher magnification. The in situ expression of Itm2a was detected in the inner enamel epithelial cells (black arrow) and odontoblasts (white arrowhead). C. An HE-stained section of the tooth germ on PN1 is shown, corresponding to the region shown in B. D. On PN1, the initiation stage of matrix formation, in situ Itm2a signals were observed in the ameloblasts (white arrow) and odontoblasts (white arrowheads). E & G. The red- and blue-boxed areas in D are shown at a higher magnification, respectively. The in situ expression of Itm2a was detected in the ameloblasts (white arrow) and odontoblasts (white arrowheads). An in situ Itm2a signal was also observed in preameloblasts (blue arrow). F & H. HE-stained sections of the tooth germ on PN1 are shown, corresponding to the regions shown in E and G, respectively. Li; lingual side, Bu; buccal side. Scale bars; 200 µm (A, D), 100 µm (B, C, E–H).

Mentions: At the late bell stage, the inner enamel epithelium became ameloblastic, and the dental pulp cells facing the inner enamel epithelium differentiated into odontoblasts (Fig. 2). Simultaneously, ameloblasts and odontoblasts secreted enamel and dentin matrices, respectively (Figs. 2D–H and 3).


Itm2a expression in the developing mouse first lower molar, and the subcellular localization of Itm2a in mouse dental epithelial cells.

Kihara M, Kiyoshima T, Nagata K, Wada H, Fujiwara H, Hasegawa K, Someya H, Takahashi I, Sakai H - PLoS ONE (2014)

The in situ expression of Itm2a mRNA in the developing tooth germ at the late bell stage.A. On PN0, the in situ expression of Itm2a was detected in the inner enamel epithelial cells (black arrow). B. The boxed area in A is shown at a higher magnification. The in situ expression of Itm2a was detected in the inner enamel epithelial cells (black arrow) and odontoblasts (white arrowhead). C. An HE-stained section of the tooth germ on PN1 is shown, corresponding to the region shown in B. D. On PN1, the initiation stage of matrix formation, in situ Itm2a signals were observed in the ameloblasts (white arrow) and odontoblasts (white arrowheads). E & G. The red- and blue-boxed areas in D are shown at a higher magnification, respectively. The in situ expression of Itm2a was detected in the ameloblasts (white arrow) and odontoblasts (white arrowheads). An in situ Itm2a signal was also observed in preameloblasts (blue arrow). F & H. HE-stained sections of the tooth germ on PN1 are shown, corresponding to the regions shown in E and G, respectively. Li; lingual side, Bu; buccal side. Scale bars; 200 µm (A, D), 100 µm (B, C, E–H).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4117645&req=5

pone-0103928-g002: The in situ expression of Itm2a mRNA in the developing tooth germ at the late bell stage.A. On PN0, the in situ expression of Itm2a was detected in the inner enamel epithelial cells (black arrow). B. The boxed area in A is shown at a higher magnification. The in situ expression of Itm2a was detected in the inner enamel epithelial cells (black arrow) and odontoblasts (white arrowhead). C. An HE-stained section of the tooth germ on PN1 is shown, corresponding to the region shown in B. D. On PN1, the initiation stage of matrix formation, in situ Itm2a signals were observed in the ameloblasts (white arrow) and odontoblasts (white arrowheads). E & G. The red- and blue-boxed areas in D are shown at a higher magnification, respectively. The in situ expression of Itm2a was detected in the ameloblasts (white arrow) and odontoblasts (white arrowheads). An in situ Itm2a signal was also observed in preameloblasts (blue arrow). F & H. HE-stained sections of the tooth germ on PN1 are shown, corresponding to the regions shown in E and G, respectively. Li; lingual side, Bu; buccal side. Scale bars; 200 µm (A, D), 100 µm (B, C, E–H).
Mentions: At the late bell stage, the inner enamel epithelium became ameloblastic, and the dental pulp cells facing the inner enamel epithelium differentiated into odontoblasts (Fig. 2). Simultaneously, ameloblasts and odontoblasts secreted enamel and dentin matrices, respectively (Figs. 2D–H and 3).

Bottom Line: A tiny amount of Itm2a was colocalized with lysosomes and endoplasmic reticulum.Minimal or no overlap between the Itm2a-EGFP signals with the other organelle markers for endoplasmic reticulum, lysosome and mitochondria used in this study noted in the cytoplasm.These findings suggest that Itm2a may play a role in cell differentiation during odontogenesis, rather than during the initiation of tooth germ formation, and may be related to the targeting of proteins associated with enamel and dentin matrices in the secretory pathway.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Oral Pathology, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan; Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.

ABSTRACT
Itm2a is a type II transmembrane protein with a BRICHOS domain. We investigated the temporospatial mRNA and protein expression patterns of Itm2a in the developing lower first molar, and examined the subcellular localization of Itm2a in murine dental epithelial (mDE6) cells. From the initiation to the bud stage, the in situ and protein signals of Itm2a were not detected in either the dental epithelial or mesenchymal cells surrounding the tooth bud. However, at the bell stage, these signals of Itm2a were primarily observed in the inner enamel epithelium of the enamel organ. After the initiation of the matrix formation, strong signals were detected in ameloblasts and odontoblasts. Itm2a showed a punctate pattern in the cytoplasm of the mDE6 cells. The perinuclear-localized Itm2a displayed a frequent overlap with the Golgi apparatus marker, GM130. A tiny amount of Itm2a was colocalized with lysosomes and endoplasmic reticulum. Minimal or no overlap between the Itm2a-EGFP signals with the other organelle markers for endoplasmic reticulum, lysosome and mitochondria used in this study noted in the cytoplasm. These findings suggest that Itm2a may play a role in cell differentiation during odontogenesis, rather than during the initiation of tooth germ formation, and may be related to the targeting of proteins associated with enamel and dentin matrices in the secretory pathway.

Show MeSH