Project description:Large offspring syndrome (LOS) and Beckwith-Wiedemann syndrome are a similar epigenetic congenital overgrowth conditions in ruminants and humans, respectively. We have reported global loss-of-imprinting, methylome epimutations, and global misregulation of genes in LOS. However, less than 4% of gene misregulation can be explained with short range (<20Kb) alterations in DNA methylation. Therefore, we hypothesized that methylome epimutations in LOS affect chromosome architecture which results in misregulation of genes located at distances >20Kb in cis and also in trans (other chromosomes). Our analyses focused on two imprinted domains that frequently show misregulation in these syndromes, namely KvDMR1 and IGF2R. Using bovine fetal fibroblasts, we identified CTCF binding at IGF2R but not KvDMR1, and allele-specific chromosome architecture of these domains in controls. In LOS, analyses identified erroneous long-range contacts and clustering tendency in the direction of expression of misregulated genes. In conclusion, altered chromosome architecture is involved in the etiology of LOS.
Project description:Large offspring syndrome (LOS) and Beckwith-Wiedemann syndrome are a similar epigenetic congenital overgrowth conditions in ruminants and humans, respectively. We have reported global loss-of-imprinting, methylome epimutations, and global misregulation of genes in LOS. However, less than 4% of gene misregulation can be explained with short range (<20Kb) alterations in DNA methylation. Therefore, we hypothesized that methylome epimutations in LOS affect chromosome architecture which results in misregulation of genes located at distances >20Kb in cis and also in trans (other chromosomes). Our analyses focused on two imprinted domains that frequently show misregulation in these syndromes, namely KvDMR1 and IGF2R. Using bovine fetal fibroblasts, we identified CTCF binding at IGF2R but not KvDMR1, and allele-specific chromosome architecture of these domains in controls. In LOS, analyses identified erroneous long-range contacts and clustering tendency in the direction of expression of misregulated genes. In conclusion, altered chromosome architecture is involved in the etiology of LOS.
Project description:Large offspring syndrome (LOS) and Beckwith-Wiedemann syndrome are a similar epigenetic congenital overgrowth conditions in ruminants and humans, respectively. We have reported global loss-of-imprinting, methylome epimutations, and global misregulation of genes in LOS. However, less than 4% of gene misregulation can be explained with short range (<20Kb) alterations in DNA methylation. Therefore, we hypothesized that methylome epimutations in LOS affect chromosome architecture which results in misregulation of genes located at distances >20Kb in cis and also in trans (other chromosomes). Our analyses focused on two imprinted domains that frequently show misregulation in these syndromes, namely KvDMR1 and IGF2R. Using bovine fetal fibroblasts, we identified CTCF binding at IGF2R but not KvDMR1, and allele-specific chromosome architecture of these domains in controls. In LOS, analyses identified erroneous long-range contacts and clustering tendency in the direction of expression of misregulated genes. In conclusion, altered chromosome architecture is involved in the etiology of LOS.
Project description:Large/abnormal offspring syndrome (LOS/AOS) is a congenital overgrowth syndrome reported in ruminants produced by assisted reproduction (ART-LOS) which exhibit global disruption of the epigenome and transcriptome. LOS/AOS shares phenotypes and epigenotypes with the human congenital overgrowth condition Beckwith-Wiedemann syndrome. We have reported that LOS occurs spontaneously (SLOS), however, to date, no study has been conducted to determine if SLOS has the same methylome epimutations as ART-LOS. In this study, we performed whole genome bisulfite sequencing to examine global DNA methylation in SLOS and ART-LOS tissues. We observed unique patterns of global distribution of differentially methylated regions (DMRs) over different genomic contexts, such as promoters, CpG islands and surrounding regions, and repetitive sequences from different treatment groups. In addition, we identified hundreds of LOS-vulnerable DMRs across different cattle breeds when analyzing four idependent LOS experiments together. Specifically, there are 25 highly vulnerable DMRs that could potentially serve as molecular markers for the diagnosis of LOS, including at the promoters of DMRT2 and TBX18, at the imprinted gene bodies of IGF2R, PRDM8, and BLCAP/NNAT, and at multiple CpG islands. We also observed tissue-specific DNA methylation patterns between muscle and blood, and conservation of ART-induced DNA methylation changes between muscle and blood. We conclude that as in ART-LOS, alterations of the epigenome are involved in the etiology of SLOS. In addition, SLOS and ART-LOS share some similarities in methylome epimutations.
Project description:Assisted reproductive therapies (ART) have become increasingly common worldwide and up to ~6% of children currently born in developed countries were conceived employing these technologies. Numerous retrospective studies have suggested that ART-conceived children are more likely to develop the overgrowth syndrome Beckwith-Wiedemann (BWS). In bovine, the use of ART can induce a similar overgrown condition, which is referred to as large offspring syndrome (LOS). Both BWS and LOS involve dysregulation of imprinted genes. However, it remains largely unknown whether aberrant gene expression and DNA methylation occur at non-imprinted loci and to what extent these molecular alterations can contribute to these syndromes. Here we examined the transcriptome of skeletal muscle, liver, kidney, and brain of control and LOS bovine fetuses and found that different LOS fetuses exhibit different severity of the transcriptome alterations and different tissues have distinct gene pathways disturbed in LOS fetuses. Particularly for skeletal muscle, multiple pathways involved in myoblast proliferation and fusion into myotubes are misregulated in LOS fetuses. Further, characterization of the methylome of skeletal muscle demonstrates numerous local methylation differences; however, global DNA methylation is comparable between all individuals regardless of bodyweight. Importantly, only a small percent of differentially expressed genes (DEGs) including the imprinted gene IGF2R can be linked to the neighboring differentially methylated regions (DMRs). In summary, we not only show that misregulation of non-imprinted genes in addition to loss-of-imprinting contributes to the ART-induced overgrowth syndrome but also demonstrate that most of the aberrant gene expression is not associated with DNA methylome epimutations.