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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 Itm2a protein expression in the tooth germ on E10.5–E14.A–D. The expression of the Itm2a protein was not observed in the epithelial or ectomesenchymal cells corresponding to the predicted lower first molar region either before or after oral epithelium thickening, or at the bud stage. The dotted lines indicate the contours of the oral epithelial layer and/or tooth bud. E & F. The boxed areas in B and D are respectively shown at a higher magnification. Li; lingual side, Bu; buccal side. Scale bars; 100 µm (A–D), 50 µm (E, F).
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pone-0103928-g005: The Itm2a protein expression in the tooth germ on E10.5–E14.A–D. The expression of the Itm2a protein was not observed in the epithelial or ectomesenchymal cells corresponding to the predicted lower first molar region either before or after oral epithelium thickening, or at the bud stage. The dotted lines indicate the contours of the oral epithelial layer and/or tooth bud. E & F. The boxed areas in B and D are respectively shown at a higher magnification. Li; lingual side, Bu; buccal side. Scale bars; 100 µm (A–D), 50 µm (E, F).

Mentions: An immunofluorescent histochemical analysis (IHC) was also carried out using an anti-Itm2a antibody. On E10.5 and E12, Itm2a protein expression was not detected in the epithelial or mesenchymal cells corresponding to the predicted lower first molar region, nor was Itm2a mRNA (Fig. 5A, B, E). At the bud stage (E13–14), Itm2a protein expression was not observed in the epithelial cells of the tooth bud or in the mesenchymal cells condensed around the tooth bud (Fig. 5C, D, F). However, the protein expression of Itm2a in the subsequent stages was detected in the developing tooth germ, and demonstrated a similar expression pattern to that of the mRNA (Figs. 5–8). Some differences were identified, including a time lag, between the mRNA and protein expression, as indicated in the respective regions below.


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 Itm2a protein expression in the tooth germ on E10.5–E14.A–D. The expression of the Itm2a protein was not observed in the epithelial or ectomesenchymal cells corresponding to the predicted lower first molar region either before or after oral epithelium thickening, or at the bud stage. The dotted lines indicate the contours of the oral epithelial layer and/or tooth bud. E & F. The boxed areas in B and D are respectively shown at a higher magnification. Li; lingual side, Bu; buccal side. Scale bars; 100 µm (A–D), 50 µm (E, F).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0103928-g005: The Itm2a protein expression in the tooth germ on E10.5–E14.A–D. The expression of the Itm2a protein was not observed in the epithelial or ectomesenchymal cells corresponding to the predicted lower first molar region either before or after oral epithelium thickening, or at the bud stage. The dotted lines indicate the contours of the oral epithelial layer and/or tooth bud. E & F. The boxed areas in B and D are respectively shown at a higher magnification. Li; lingual side, Bu; buccal side. Scale bars; 100 µm (A–D), 50 µm (E, F).
Mentions: An immunofluorescent histochemical analysis (IHC) was also carried out using an anti-Itm2a antibody. On E10.5 and E12, Itm2a protein expression was not detected in the epithelial or mesenchymal cells corresponding to the predicted lower first molar region, nor was Itm2a mRNA (Fig. 5A, B, E). At the bud stage (E13–14), Itm2a protein expression was not observed in the epithelial cells of the tooth bud or in the mesenchymal cells condensed around the tooth bud (Fig. 5C, D, F). However, the protein expression of Itm2a in the subsequent stages was detected in the developing tooth germ, and demonstrated a similar expression pattern to that of the mRNA (Figs. 5–8). Some differences were identified, including a time lag, between the mRNA and protein expression, as indicated in the respective regions below.

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