Project description:BACKGROUND: Orofacial development is a multifaceted process involving precise, spatio-temporal expression of a panoply of genes. MicroRNAs (miRNAs) constitute the largest family of noncoding RNAs involved in gene silencing, and represent critical regulators of cell and tissue differentiation. MicroRNA gene expression profiling is an effective means of acquiring novel and valuable information regarding the expression and regulation of genes, under the control of miRNA, involved in mammalian orofacial development. RESULTS: To identify differentially expressed miRNAs during mammalian orofacial ontogenesis, miRNA expression profiles from gestation day (GD) -12, -13 and -14 murine orofacial tissue were compared utilizing miRXplore™ microarrays from Miltenyi Biotech GmbH. TaqManTM quantitative Real-Time PCR was utilized for validation of gene expression changes. Cluster analysis of the microarray data was conducted with the clValid R package and the UPGMA (hierarchical) clustering method. Functional relationships between selected miRNAs were investigated using Ingenuity Pathway Analysis. Expression of over 26% of the approximately 588 murine miRNA genes examined was detected in murine orofacial tissues from GD 12, 13 and 14. Among these expressed genes several clusters were seen to be developmentally regulated. Differential expression of genes encoding miRNAs within such clusters were shown to target genes encoding proteins involved in cell proliferation, cell adhesion, differentiation, apoptosis and epithelial-mesenchymal transformation, all processes critical for normal orofacial development. Functional relationships between miRNAs differentially expressed were investigated using Ingenuity Pathway Analysis (IPA; Ingenuity Systems). CONCLUSIONS: Using miRNA microarray technology, unique gene expression signatures of hundreds of miRNAs in embryonic orofacial tissue were defined. Gene targeting and functional analysis revealed that the expression of numerous protein-encoding genes, crucial to normal orofacial ontogeny, may be regulated by specific miRNAs. Time-course experiment (Developmental Stages), ICR mice embryos on gestational days (GD) 12, 13 and 14. Biological replicates: For each day of gestation, 3 independent pools of 15 to 20 staged embryos were used to procure embryonic orofacial tissues for preparation of 3 distinct pools of RNA that were independently processed and applied to individual miRXplore™ microRNA Microarray chips (Miltenyi Biotec GmbH). Technology: 2-color spotted cDNA, Hy5 (experimental sample) vs. Hy3 (control - miRXplore Universal Reference).

Project description:BACKGROUND: Orofacial development is a multifaceted process involving precise, spatio-temporal expression of a panoply of genes. MicroRNAs (miRNAs) constitute the largest family of noncoding RNAs involved in gene silencing, and represent critical regulators of cell and tissue differentiation. MicroRNA gene expression profiling is an effective means of acquiring novel and valuable information regarding the expression and regulation of genes, under the control of miRNA, involved in mammalian orofacial development. RESULTS: To identify differentially expressed miRNAs during mammalian orofacial ontogenesis, miRNA expression profiles from gestation day (GD) -12, -13 and -14 murine orofacial tissue were compared utilizing miRXplore™ microarrays from Miltenyi Biotech GmbH. TaqManTM quantitative Real-Time PCR was utilized for validation of gene expression changes. Cluster analysis of the microarray data was conducted with the clValid R package and the UPGMA (hierarchical) clustering method. Functional relationships between selected miRNAs were investigated using Ingenuity Pathway Analysis. Expression of over 26% of the approximately 588 murine miRNA genes examined was detected in murine orofacial tissues from GD 12, 13 and 14. Among these expressed genes several clusters were seen to be developmentally regulated. Differential expression of genes encoding miRNAs within such clusters were shown to target genes encoding proteins involved in cell proliferation, cell adhesion, differentiation, apoptosis and epithelial-mesenchymal transformation, all processes critical for normal orofacial development. Functional relationships between miRNAs differentially expressed were investigated using Ingenuity Pathway Analysis (IPA; Ingenuity Systems). CONCLUSIONS: Using miRNA microarray technology, unique gene expression signatures of hundreds of miRNAs in embryonic orofacial tissue were defined. Gene targeting and functional analysis revealed that the expression of numerous protein-encoding genes, crucial to normal orofacial ontogeny, may be regulated by specific miRNAs.

Project description:The cranial neural crest plays a fundamental role in orofacial development and morphogenesis. As a pluripotent and dynamic cell population, the cranial neural crest is undergoing vast transcriptional alterations throughout embryogenesis and the formation of facial structures. These transcriptional changes are regulated by several transcription factors and remodeling complexes. Previously, we revealed the relevance of the Ep400/Kat5 histone acetyltransferase complex in the cranial neural crest and showed that the knockout of Ep400 causes neural crest-related malformations such as orofacial clefting. Furthermore, a case study identified three patients carrying missense mutations in Kat5 who showed severe mental impairments as well as orofacial clefts.2 The exact molecular causes and mechanisms, however, are still unknown. In this study we selectively knocked out Ep400 or Kat5 in the murine cranial neural crest cell line O9-1 to examine its roles in neural crest biology. To understand the regulatory effects of Ep400 and Kat5, knockout neural crest cells were investigated via bulk RNA sequencing to unravel transcriptomic changes in the affected cells. Bioinformatic analyses hinted at the regulation of major cellular functions such as proliferation, ATP generation and protein synthesis by the Ep400/Kat5 complex. Reduced proliferation was confirmed by crystal violet staining, phospho-histone H3 staining and the determination of mitotic cells with condensed chromatin in vitro. We did not detect increased apoptosis in the knockout cell lines. The energetic profile of the cells was investigated by Seahorse technology. The ATP-rate assay showed a decreased glycolytic activity in Ep400- or Kat5-deficient cells. An O-propargyl-puromycin (OPP) Click-iT assay revealed a significant reduction in protein synthesis. To verify in vivo the discovered in vitro effects, Ep400 and Kat5 were selectively ablated in cranial neural crest using Wnt1-Cre in transgenic mice. The knockout of each of the subunits resulted in severe craniofacial malformations from E12.5 onwards. At E10.5 a significant reduction in neural crest-derived tissue and proliferation rate was evident. The strong defect in orofacial structures of mice lacking Kat5 or Ep400 completely correspond to the milder orofacial malformations in patients carrying heterozygous missense mutations. Our results furthermore argue that changes of metabolism, protein synthesis and proliferation in cranial neural crest cells are responsible for the orofacial defects observed in patients.

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Transcriptome analysis of Xenopus orofacial tissues deficient in retinoic acid receptor function

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