Gene expression during palate fusion in vivo and in vitro.
Failure of secondary palate fusion during embryogenesis is a cause of cleft palate. Disappearance of the medial epithelial seam (MES) is required to allow merging of the mesenchyme from both palatal shelves. This involves complex changes of the medial edge epithelial (MEE) cells and surrounding structures that are controlled by several genes whose spatio-temporal expression is tightly regulated. We have carried out morphological analyses and used a semi-quantitative RT-PCR technique to evaluate whether morphological changes and modulation in the expression of putative key genes, such as twist, snail, and E-cadherin, during the fusion process in palate organ culture parallel those observed in vivo, and show that this is indeed the case. We also show, using the organotypic model of palate fusion, that the down-regulation of the transcription factor snail that occurs with the progression of palate development is not dependent on fusion of the palatal shelves.


BACKGROUND
dsg1, desmoglein1; EMT, epithelial-mesenchymal transition; MEE, medial edge epithelium; MES, medial epithelial seam; RT-PCR, reverse-transcriptase polymerase chain-reaction.
Pungchanchaikul
P
P
Developmental Biology Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
Gelbier
M
M
Ferretti
P
P
Bloch-Zupan
A
A
D000818:Animals; D015820:Cadherins / Q000235:genetics; D051183:Desmoglein 1; D015536:Down-Regulation / Q000235:genetics; D004847:Epithelial Cells / Q000502:physiology; D004848:Epithelium / Q000196:embryology; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D053569:Keratin-15; D053555:Keratin-5; D007633:Keratins / Q000235:genetics; D008648:Mesoderm / Q000502:physiology; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics; D009924:Organ Culture Techniques; D010159:Palate / Q000196:embryology*; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics; D051879:Twist-Related Protein 1; D016335:Zinc Fingers / Q000235:genetics
D015820:Cadherins; D051183:Desmoglein 1; D053569:Keratin-15; D053555:Keratin-5; C492053:Krt15 protein, mouse; D009687:Nuclear Proteins; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D051879:Twist-Related Protein 1; D007633:Keratins