Project description:Given the possible critical importance of placental gene imprinting and random monoallelic expression on fetal and infant health, most of those genes must be identified, in order to understand the risks that the baby might meet during pregnancy and after birth. Therefore, the aim of the current study was to introduce a workflow and tools for analyzing imprinted and random monoallelic gene expression in human placenta, by applying whole-transcriptome (WT) RNA sequencing of placental tissue and genotyping of coding DNA variants in family trios. Ten family trios, each with a healthy spontaneous single-term pregnancy, were recruited. Total RNA was extracted for WT analysis, providing the full sequence information for the placental transcriptome. Parental and child blood DNA genotypes were analyzed by exome SNP genotyping microarrays, mapping the inheritance and estimating the abundance of parental expressed alleles. Imprinted genes showed consistent expression from either parental allele, as demonstrated by the SNP content of sequenced transcripts, while monoallelically expressed genes had random activity of parental alleles. We revealed 4 novel possible imprinted genes (LGALS8, LGALS14, PAPPA2 and SPTLC3) and confirmed the imprinting of 4 genes (AIM1, PEG10, RHOBTB3 and ZFAT-AS1) in human placenta. The major finding was the identification of 4 genes (ABP1, BCLAF1, IFI30 and ZFAT) with random allelic bias, expressing one of the parental alleles preferentially. The main functions of the imprinted and monoallelically expressed genes included: i) mediating cellular apoptosis and tissue development; ii) regulating inflammation and immune system; iii) facilitating metabolic processes; and iv) regulating cell cycle. Placentas from ten family trios were analysed using RNA-Seq.
Project description:Given the possible critical importance of placental gene imprinting and random monoallelic expression on fetal and infant health, most of those genes must be identified, in order to understand the risks that the baby might meet during pregnancy and after birth. Therefore, the aim of the current study was to introduce a workflow and tools for analyzing imprinted and random monoallelic gene expression in human placenta, by applying whole-transcriptome (WT) RNA sequencing of placental tissue and genotyping of coding DNA variants in family trios. Ten family trios, each with a healthy spontaneous single-term pregnancy, were recruited. Total RNA was extracted for WT analysis, providing the full sequence information for the placental transcriptome. Parental and child blood DNA genotypes were analyzed by exome SNP genotyping microarrays, mapping the inheritance and estimating the abundance of parental expressed alleles. Imprinted genes showed consistent expression from either parental allele, as demonstrated by the SNP content of sequenced transcripts, while monoallelically expressed genes had random activity of parental alleles. We revealed 4 novel possible imprinted genes (LGALS8, LGALS14, PAPPA2 and SPTLC3) and confirmed the imprinting of 4 genes (AIM1, PEG10, RHOBTB3 and ZFAT-AS1) in human placenta. The major finding was the identification of 4 genes (ABP1, BCLAF1, IFI30 and ZFAT) with random allelic bias, expressing one of the parental alleles preferentially. The main functions of the imprinted and monoallelically expressed genes included: i) mediating cellular apoptosis and tissue development; ii) regulating inflammation and immune system; iii) facilitating metabolic processes; and iv) regulating cell cycle.
Project description:Given the possible critical importance of placental gene imprinting and random monoallelic expression on fetal and infant health, most of those genes must be identified, in order to understand the risks that the baby might meet during pregnancy and after birth. Therefore, the aim of the current study was to introduce a workflow and tools for analyzing imprinted and random monoallelic gene expression in human placenta, by applying whole-transcriptome (WT) RNA sequencing of placental tissue and genotyping of coding DNA variants in family trios. Ten family trios, each with a healthy spontaneous single-term pregnancy, were recruited. Total RNA was extracted for WT analysis, providing the full sequence information for the placental transcriptome. Parental and child blood DNA genotypes were analyzed by exome SNP genotyping microarrays, mapping the inheritance and estimating the abundance of parental expressed alleles. Imprinted genes showed consistent expression from either parental allele, as demonstrated by the SNP content of sequenced transcripts, while monoallelically expressed genes had random activity of parental alleles. We revealed 4 novel possible imprinted genes (LGALS8, LGALS14, PAPPA2 and SPTLC3) and confirmed the imprinting of 4 genes (AIM1, PEG10, RHOBTB3 and ZFAT-AS1) in human placenta. The major finding was the identification of 4 genes (ABP1, BCLAF1, IFI30 and ZFAT) with random allelic bias, expressing one of the parental alleles preferentially. The main functions of the imprinted and monoallelically expressed genes included: i) mediating cellular apoptosis and tissue development; ii) regulating inflammation and immune system; iii) facilitating metabolic processes; and iv) regulating cell cycle.
Project description:Fetal health is dependent upon the epigenetic-based regulation of gene expression in placenta. Genomic imprinting is an epigenetic phenomenon common to placenta and refers to the monoallelic expression of a gene in a parental-specific manner. We aimed to detect novel imprinted genes in human placenta by applying whole transcriptome RNA-sequencing and genotyping of coding variants. Ten family trios with healthy spontaneous single term pregnancy were recruited. Parental and child DNA genotypes were analysed using exome SNP genotyping microarrays, revealing the inheritance of parental alleles. Total RNA was extracted from placental tissue for whole transcriptome analysis. The imprinted genes showed consistent expression from either parental allele as demonstrated by the SNP content of sequenced transcripts. We found seven novel imprinted genes (ABP1, BCLAF1, IFI30, LGALS8, LGALS14, PAPPA2 and SPTLC3) and confirmed five known imprinted genes (AIM1, PEG10, RHOBTB3, ZFAT and ZFAT-AS1). The main functions of the proteins encoded by the imprinted genes can be grouped as being involved in: i) cellular apoptosis and tissue development; ii) regulating inflammation and modulating the immune system; iii) facilitating metabolic processes and iv) regulating the cell cycle. Ten family trios (mother, father, child) were analysed using SNP genotyping. Raw data contains additional two samples that were not used.
Project description:Parent-of-origin dependent expression of alleles, imprinting, has been suggested to impact a substantial proportion of mammalian genes. Its discovery requires allele-specific detection of expressed transcripts, but in some cases detected allelic expression (AE) bias has been interpreted as imprinting without demonstrating compatible transmission patterns and excluding heritable variation. Therefore, we utilized a genome-wide tool exploiting high density genotyping arrays in parallel measurements of genotypes in RNA and DNA to determine AE across the transcriptome in lymphoblastoid cell lines (LCLs) and skin fibroblasts derived from families. To investigate imprinting, transmission patterns were analyzed in 2 LCL trios, 1 LCL 3-generation pedigree and 9 FB trios. To investigate random monoallelic expression, 2 cell lines were treated with three concentrations of 5-azadeoxycytidine (AZA), and one cell line was treated for two time periods.
Project description:Random monoallelic expression is defined by the allele-specific expression of genes, and by the fact that for an individual cell this monoallelic expression is neither obligate nor necessarily coordinated with the allelic expression in other cells. In order to find novel examples of random monoallelic expression in mouse, we did a transcriptome-wide survey of allele-specific gene expression in two different immortalized cell types. Lymphoblast cell lines and fibroblast cell lines were established (both clonal and nonclonal) and were used as a source of both nuclear RNA and genomic DNA. These samples were assessed for allele-specific gene expression using a custom-designed Mouse SNP Chip. A large number of genes (over 10% of those that were assessed in lymphoblast clones) displayed random monoallelic expression.
Project description:Random monoallelic expression is defined by the allele-specific expression of genes, and by the fact that for an individual cell this monoallelic expression is neither obligate nor necessarily coordinated with the allelic expression in other cells. In order to find novel examples of random monoallelic expression in mouse, we did a transcriptome-wide survey of allele-specific gene expression in two different immortalized cell types. Lymphoblast cell lines and fibroblast cell lines were established (both clonal and nonclonal) and were used as a source of both nuclear RNA and genomic DNA. These samples were assessed for allele-specific gene expression using a custom-designed Mouse SNP Chip. A large number of genes (over 10% of those that were assessed in lymphoblast clones) displayed random monoallelic expression. For each cell line, two replicate samples of ds-cDNA were assessed for monoallelic expression, while genomic DNA was assessed as a control for possible LOH events. Nonclonal samples were used as controls for cis-acting allelic bias.