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Molecular signaling along the anterior-posterior axis of early palate development.

Smith TM, Lozanoff S, Iyyanar PP, Nazarali AJ - Front Physiol (2013)

Bottom Line: In mammals, the palatal tissue can be distinguished into anterior bony hard palate and posterior muscular soft palate that have specialized functions in occlusion, speech or swallowing.Numerous transcription factors and signaling pathways are now recognized as either anterior- (e.g., Msx1, Bmp4, Bmp2, Shh, Spry2, Fgf10, Fgf7, and Shox2) or posterior-specific (e.g., Meox2, Tbx22, and Barx1).We hypothesize that the anterior palate acts as a signaling center in setting up development of the secondary palate.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Cell Biology, College of Pharmacy and Nutrition, University of Saskatchewan Saskatoon, SK, Canada.

ABSTRACT
Cleft palate is a common congenital birth defect in humans. In mammals, the palatal tissue can be distinguished into anterior bony hard palate and posterior muscular soft palate that have specialized functions in occlusion, speech or swallowing. Regulation of palate development appears to be the result of distinct signaling and genetic networks in the anterior and posterior regions of the palate. Development and maintenance of expression of these region-specific genes is crucial for normal palate development. Numerous transcription factors and signaling pathways are now recognized as either anterior- (e.g., Msx1, Bmp4, Bmp2, Shh, Spry2, Fgf10, Fgf7, and Shox2) or posterior-specific (e.g., Meox2, Tbx22, and Barx1). Localized expression and function clearly highlight the importance of regional patterning and differentiation within the palate at the molecular level. Here, we review how these molecular pathways and networks regulate the anterior-posterior patterning and development of secondary palate. We hypothesize that the anterior palate acts as a signaling center in setting up development of the secondary palate.

No MeSH data available.


Related in: MedlinePlus

At E13.5, the anterior palatal shelves first flip up to orient vertically when the posterior palatal shelves are still lying horizontal to each other (A). At E14, the posterior palatal shelves follow the anterior palatal shelves in orienting vertically, whereas the anterior palates begin to grow vertically toward each other to make contact (B). At E15, the anterior palatal shelves have made contact and fused, whereas the posterior shelves grow vertically (C). At E15.5, both the anterior and posterior palates have fused (D). At E16, the fusion between the primary and secondary palate occurs at the future secondary choana (E). Palatal shelves are divided into anterior (pink) Msx1 and posterior (aqua) Barx1 expression domains (A–E) representing future hard and soft palate, respectively. Fgf-Bmp gradients/thresholds maintain proper palatal growth and fusion through proliferation. Anterior Fgf10 and Bmps control proliferation via Shh expression. This directs anterior palate flip up and vertical growth at E13.5–E14 (A,B). Anterior Fgf-Bmp gradients along with posterior Fgf8 regulate proliferation and growth via Barx1 in the posterior palate at E14–E15 (B,C). Fusion is initiated at the anterior palate by Tgf-β3 through its receptor (C). Then the fusion extends posteriorly through Tgf-β-Meox2 (D). The fusion between the primary and secondary palate marks the completion of palatal fusion at E16 (D,E), via Bmpr1a mediated Shox2 and Tgf β signaling through its receptors.
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Figure 4: At E13.5, the anterior palatal shelves first flip up to orient vertically when the posterior palatal shelves are still lying horizontal to each other (A). At E14, the posterior palatal shelves follow the anterior palatal shelves in orienting vertically, whereas the anterior palates begin to grow vertically toward each other to make contact (B). At E15, the anterior palatal shelves have made contact and fused, whereas the posterior shelves grow vertically (C). At E15.5, both the anterior and posterior palates have fused (D). At E16, the fusion between the primary and secondary palate occurs at the future secondary choana (E). Palatal shelves are divided into anterior (pink) Msx1 and posterior (aqua) Barx1 expression domains (A–E) representing future hard and soft palate, respectively. Fgf-Bmp gradients/thresholds maintain proper palatal growth and fusion through proliferation. Anterior Fgf10 and Bmps control proliferation via Shh expression. This directs anterior palate flip up and vertical growth at E13.5–E14 (A,B). Anterior Fgf-Bmp gradients along with posterior Fgf8 regulate proliferation and growth via Barx1 in the posterior palate at E14–E15 (B,C). Fusion is initiated at the anterior palate by Tgf-β3 through its receptor (C). Then the fusion extends posteriorly through Tgf-β-Meox2 (D). The fusion between the primary and secondary palate marks the completion of palatal fusion at E16 (D,E), via Bmpr1a mediated Shox2 and Tgf β signaling through its receptors.

Mentions: Critical events such as elevation, maturation and fusion of secondary palatal shelves follow an anterior to posterior sequence (Taya et al., 1999; Dudas et al., 2004) (Figure 4). During mouse palate development, at embryonic day E13.5–E14, the anterior palate orients horizontally above the tongue when the posterior palate is still lying vertically (Kaufman, 1992) providing a clear indication of the more dynamic growth in the anterior palate compared to the posterior palate. In addition, the initial site of apposition and subsequent fusion of the palatal shelves occur first in the anterior half of the palate and the sequence of palatal closure may be result of signaling activity along the A–P axis.


Molecular signaling along the anterior-posterior axis of early palate development.

Smith TM, Lozanoff S, Iyyanar PP, Nazarali AJ - Front Physiol (2013)

At E13.5, the anterior palatal shelves first flip up to orient vertically when the posterior palatal shelves are still lying horizontal to each other (A). At E14, the posterior palatal shelves follow the anterior palatal shelves in orienting vertically, whereas the anterior palates begin to grow vertically toward each other to make contact (B). At E15, the anterior palatal shelves have made contact and fused, whereas the posterior shelves grow vertically (C). At E15.5, both the anterior and posterior palates have fused (D). At E16, the fusion between the primary and secondary palate occurs at the future secondary choana (E). Palatal shelves are divided into anterior (pink) Msx1 and posterior (aqua) Barx1 expression domains (A–E) representing future hard and soft palate, respectively. Fgf-Bmp gradients/thresholds maintain proper palatal growth and fusion through proliferation. Anterior Fgf10 and Bmps control proliferation via Shh expression. This directs anterior palate flip up and vertical growth at E13.5–E14 (A,B). Anterior Fgf-Bmp gradients along with posterior Fgf8 regulate proliferation and growth via Barx1 in the posterior palate at E14–E15 (B,C). Fusion is initiated at the anterior palate by Tgf-β3 through its receptor (C). Then the fusion extends posteriorly through Tgf-β-Meox2 (D). The fusion between the primary and secondary palate marks the completion of palatal fusion at E16 (D,E), via Bmpr1a mediated Shox2 and Tgf β signaling through its receptors.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539680&req=5

Figure 4: At E13.5, the anterior palatal shelves first flip up to orient vertically when the posterior palatal shelves are still lying horizontal to each other (A). At E14, the posterior palatal shelves follow the anterior palatal shelves in orienting vertically, whereas the anterior palates begin to grow vertically toward each other to make contact (B). At E15, the anterior palatal shelves have made contact and fused, whereas the posterior shelves grow vertically (C). At E15.5, both the anterior and posterior palates have fused (D). At E16, the fusion between the primary and secondary palate occurs at the future secondary choana (E). Palatal shelves are divided into anterior (pink) Msx1 and posterior (aqua) Barx1 expression domains (A–E) representing future hard and soft palate, respectively. Fgf-Bmp gradients/thresholds maintain proper palatal growth and fusion through proliferation. Anterior Fgf10 and Bmps control proliferation via Shh expression. This directs anterior palate flip up and vertical growth at E13.5–E14 (A,B). Anterior Fgf-Bmp gradients along with posterior Fgf8 regulate proliferation and growth via Barx1 in the posterior palate at E14–E15 (B,C). Fusion is initiated at the anterior palate by Tgf-β3 through its receptor (C). Then the fusion extends posteriorly through Tgf-β-Meox2 (D). The fusion between the primary and secondary palate marks the completion of palatal fusion at E16 (D,E), via Bmpr1a mediated Shox2 and Tgf β signaling through its receptors.
Mentions: Critical events such as elevation, maturation and fusion of secondary palatal shelves follow an anterior to posterior sequence (Taya et al., 1999; Dudas et al., 2004) (Figure 4). During mouse palate development, at embryonic day E13.5–E14, the anterior palate orients horizontally above the tongue when the posterior palate is still lying vertically (Kaufman, 1992) providing a clear indication of the more dynamic growth in the anterior palate compared to the posterior palate. In addition, the initial site of apposition and subsequent fusion of the palatal shelves occur first in the anterior half of the palate and the sequence of palatal closure may be result of signaling activity along the A–P axis.

Bottom Line: In mammals, the palatal tissue can be distinguished into anterior bony hard palate and posterior muscular soft palate that have specialized functions in occlusion, speech or swallowing.Numerous transcription factors and signaling pathways are now recognized as either anterior- (e.g., Msx1, Bmp4, Bmp2, Shh, Spry2, Fgf10, Fgf7, and Shox2) or posterior-specific (e.g., Meox2, Tbx22, and Barx1).We hypothesize that the anterior palate acts as a signaling center in setting up development of the secondary palate.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Cell Biology, College of Pharmacy and Nutrition, University of Saskatchewan Saskatoon, SK, Canada.

ABSTRACT
Cleft palate is a common congenital birth defect in humans. In mammals, the palatal tissue can be distinguished into anterior bony hard palate and posterior muscular soft palate that have specialized functions in occlusion, speech or swallowing. Regulation of palate development appears to be the result of distinct signaling and genetic networks in the anterior and posterior regions of the palate. Development and maintenance of expression of these region-specific genes is crucial for normal palate development. Numerous transcription factors and signaling pathways are now recognized as either anterior- (e.g., Msx1, Bmp4, Bmp2, Shh, Spry2, Fgf10, Fgf7, and Shox2) or posterior-specific (e.g., Meox2, Tbx22, and Barx1). Localized expression and function clearly highlight the importance of regional patterning and differentiation within the palate at the molecular level. Here, we review how these molecular pathways and networks regulate the anterior-posterior patterning and development of secondary palate. We hypothesize that the anterior palate acts as a signaling center in setting up development of the secondary palate.

No MeSH data available.


Related in: MedlinePlus