Position-dependent correlation between TBX22 exon 5 methylation and palatal shelf fusion in the development of cleft palate.

Ke Li,Hui Gong,Xuan Shu,Liuhanghang Cheng,Shenyou Shu,Zejun Dong

doi:10.1590/0001-3765201920180945

Abstract

DNA methylation is essential for spatiotemporally-regulated gene expression in embryonic development. TBX22 (Chr X: 107667964-107688978) functioning as a transcriptional repressor affects DNA binding, sumoylation, and transcriptional repression associated with X-linked cleft palate. This study aimed to explore the relationship and potential mechanism between TBX22 exon 5 methylation and palatal shelf fusion induced by all-trans retinoic acid (ATRA). We performed DNA methylation profiling, using MethylRAD-seq, after high throughput sequencing of mouse embryos from control (n=9) and ATRA-treated (to induce cleft palate, n=9) C57BL/6J mice at embryonic gestation days(E) 13.5, 14.5 and 16.5. TBX22 exon 5 was hyper-methylated at the CpG site at E13.5 (P=0.025, log2FC=1.5) and E14.5 (P=0.011, log2FC:1.5) in ATRA-treated, whereas methylation TBX22 exon 5 at the CpG site was not significantly different at E16.5 (P=0.808, log2FC=-0.2) between control and ATRA-treated. MSP results showed a similar trend consistent with the MethylRAD-seq results. qPCR showed the change in TBX22 exon 5 expression level negatively correlated with its TBX22 exon 5 methylation level. These results indicate that changes in TBX22 exon 5 methylation might play an important regulatory role during palatal shelf fusion, and may enlighten the development of novel epigenetic biomarkers in the treatment of CP in the future.

Highlights

DNA methylation is an epigenetic event that plays an essential role in the regulation of temporal and spatial gene expression during embryonic development (Shiota 2004)
Palatal fusion involves temporal and spatialregulated disruption of embryonic palatal medial edge epithelia (MEE), and dynamic cellular and molecular processes that result in adhesion and intercalation of the embryonic MEE to form an inter-shelf epithelial seam, and subsequent remodeling and fusion to form the intact roof of the oral cavity (Rice 2005, Thiery and Sleeman 2006, Nawshad 2008, Bush and Jiang 2012, Lan et al 2015)
It is not clear whether TBX22 exon 5 methylation is involved embryonic palatal shelf fusion induced by maternal exposure to all-trans retinoic acid (ATRA)

Summary

Introduction

DNA methylation is an epigenetic event that plays an essential role in the regulation of temporal and spatial gene expression during embryonic development (Shiota 2004). It is the process by which a methyl group is added to a DNA molecule. DNA methylation can significantly increase the rate of spontaneous C→T mutations at CpG dinucleotides (Ehrlich and Wang 1981, Hwang and Green 2004, Mugal and Ellengren 2011). It is not clear whether TBX22 exon 5 methylation is involved embryonic palatal shelf fusion induced by maternal exposure to all-trans retinoic acid (ATRA)

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Methods

Results

Conclusion