scholarly journals Discovering candidate imprinted genes and Imprinting Control Regions in the human genome

2019 ◽  
Author(s):  
Minou Bina

ABSTRACTGenomic imprinting is a process thereby a subset of genes is expressed in a parent-of-origin specific manner. This evolutionary novelty is restricted to mammals and controlled by genomic DNA segments known as Imprinting Control Regions (ICRs). The known imprinted genes function in many important developmental and postnatal processes including organogenesis, neurogenesis, and fertility. Furthermore, defects in imprinted genes could cause severe diseases and abnormalities. Because of the importance of the ICRs to the regulation of parent-of-origin specific gene expression, I developed a genome-wide strategy for their localization. This strategy located clusters of the ZFBS-Morph overlaps along the entire human genome. Previously, I showed that in the mouse genome, clusters of 2 or more of these overlaps correctly located ∼ 90% of the fully characterized ICRs and germline Differentially Methylated Regions (gDMRs). The ZFBS-Morph overlaps are composite-DNA-elements comprised of the ZFP57 binding site (ZFBS) overlapping a subset of the MLL1 morphemes. My strategy consists of creating plots to display the density of ZFBS-Morph overlaps along genomic DNA. Peaks in these plots pinpointed several of the known ICRs/gDMRs within relatively long genomic DNA sections and even along entire chromosomal DNA. Therefore, peaks in the density-plots are likely to reflect the positions of known or candidate ICRs. I also found that by locating the genes in the vicinity of candidate ICRs, I could discover potential and novel human imprinting genes. Additionally, my exploratory assessments revealed a connection between several of the potential imprinted genes and human developmental anomalies including syndromes.

2019 ◽  
Author(s):  
Minou Bina ◽  
Phillip Wyss

ABSTRACTIn mammals, parent-of-origin-specific gene expression is regulated by specific genomic DNA segments known as Imprinting Control Regions (ICRs) and germline Differentially Methylated Regions (gDMRs). In the mouse genome, the known ICRs/gDMRs often include clusters of a set of composite-DNA-elements known as ZFBS-morph overlaps. These elements consist of the ZFP57 binding site (ZFBS) overlapping a subset of the MLL1 morphemes. To improve detection of such clusters, we created density-plots. In genome-wide analyses, peaks in these plots pinpointed ∼90% of the known ICRs/gDMRs and located candidate ICRs within relatively long genomic DNA sections. In several cases, the candidate ICRs mapped to chromatin boundaries, to a subset of gene-transcripts, or to both. By viewing the plots at the UCSC genome browser, we could examine the candidate ICRs in the context of the genes in their vicinity. This strategy uncovered several potential imprinted genes with a broad range of physiologically important functions. Examples include: folliculogenesis; lineage commitment of murine embryonic stem cells; the development of the junctional zone of the placenta; left-right patterning of the body axis; the development of the neocortex, hippocampus, and cerebellum; postnatal vision; self-renewal of mouse spermatogonial stem cells; and histone-to-protamine replacement during spermatogenesis.


2021 ◽  
Author(s):  
Phillip Wyss ◽  
Carol Song ◽  
Minou Bina

In mammals, Imprinting Control Regions (ICRs) regulate a subset of genes in a parent-of-origin-specific manner. In both human and mouse, previous studies identified a set of CpG-rich motifs that occurred as clusters in ICRs and germline Differentially Methylated Regions (gDMRs). These motifs consist of the ZFP57 binding site (ZFBS) overlapping a subset of MLL binding units known as MLL morphemes. Furthermore, by creating plots for displaying the density of these overlaps, it became possible to locate known and candidate ICRs in mouse and human genomic DNA. Since genomic imprinting impacts many developmental and key physiological processes, we performed genome-wide analyses to create plots displaying the density of the CpG-rich motifs (ZFBS-morph overlaps) along Bos Taurus chromosomal DNA. We tailored our datasets so that they could be displayed on the UCSC genome browser (the build bosTau8). On the genome browser, we could view the ZFP57 binding sites, the ZFBS-morph overlaps, and peaks in the density-plots in the context of cattle RefSeq Genes, Non-Cow RefSeq Genes, CpG islands, and Single nucleotide polymorphisms (SNPs). Our datasets revealed the correspondence of peaks in plots to known and deduced ICRs in Bos Taurus genomic DNA. We illustrate that by uploading our datasets onto the UCSC genome browser, we could discover candidate ICRs in cattle DNA. In enlarged views, we could pinpoint the genes in the vicinity of candidate ICRs and thus discover potential imprinted genes.


PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243791
Author(s):  
Caitlin Mills ◽  
Anushya Muruganujan ◽  
Dustin Ebert ◽  
Crystal N. Marconett ◽  
Juan Pablo Lewinger ◽  
...  

Enhancers are powerful and versatile agents of cell-type specific gene regulation, which are thought to play key roles in human disease. Enhancers are short DNA elements that function primarily as clusters of transcription factor binding sites that are spatially coordinated to regulate expression of one or more specific target genes. These regulatory connections between enhancers and target genes can therefore be characterized as enhancer-gene links that can affect development, disease, and homeostatic cellular processes. Despite their implication in disease and the establishment of cell identity during development, most enhancer-gene links remain unknown. Here we introduce a new, publicly accessible database of predicted enhancer-gene links, PEREGRINE. The PEREGRINE human enhancer-gene links interactive web interface incorporates publicly available experimental data from ChIA-PET, eQTL, and Hi-C assays across 78 cell and tissue types to link 449,627 enhancers to 17,643 protein-coding genes. These enhancer-gene links are made available through the new Enhancer module of the PANTHER database and website where the user may easily access the evidence for each enhancer-gene link, as well as query by target gene and enhancer location.


PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1527 ◽  
Author(s):  
Nick Kamps-Hughes ◽  
Jessica L. Preston ◽  
Melissa A. Randel ◽  
Eric A. Johnson

Here we present a genome-wide method forde novoidentification of enhancer regions. This approach enables massively parallel empirical investigation of DNA sequences that mediate transcriptional activation and provides a platform for discovery of regulatory modules capable of driving context-specific gene expression. The method links fragmented genomic DNA to the transcription of randomer molecule identifiers and measures the functional enhancer activity of the library by massively parallel sequencing. We transfected aDrosophila melanogasterlibrary into S2 cells in normoxia and hypoxia, and assayed 4,599,881 genomic DNA fragments in parallel. The locations of the enhancer regions strongly correlate with genes up-regulated after hypoxia and previously described enhancers. Novel enhancer regions were identified and integrated with RNAseq data and transcription factor motifs to describe the hypoxic response on a genome-wide basis as a complex regulatory network involving multiple stress-response pathways. This work provides a novel method for high-throughput assay of enhancer activity and the genome-scale identification of 31 hypoxia-activated enhancers inDrosophila.


2013 ◽  
Author(s):  
Benjamin P. Berman ◽  
Yaping Liu ◽  
Theresa K. Kelly

Background: Nucleosome organization and DNA methylation are two mechanisms that are important for proper control of mammalian transcription, as well as epigenetic dysregulation associated with cancer. Whole-genome DNA methylation sequencing studies have found that methylation levels in the human genome show periodicities of approximately 190 bp, suggesting a genome-wide relationship between the two marks. A recent report (Chodavarapu et al., 2010) attributed this to higher methylation levels of DNA within nucleosomes. Here, we analyzed a number of published datasets and found a more compelling alternative explanation, namely that methylation levels are highest in linker regions between nucleosomes. Results: Reanalyzing the data from (Chodavarapu et al., 2010), we found that nucleosome-associated methylation could be strongly confounded by known sequence-related biases of the next-generation sequencing technologies. By accounting for these biases and using an unrelated nucleosome profiling technology, NOMe-seq, we found that genome-wide methylation was actually highest within linker regions occurring between nucleosomes in multi-nucleosome arrays. This effect was consistent among several methylation datasets generated independently using two unrelated methylation assays. Linker-associated methylation was most prominent within long Partially Methylated Domains (PMDs) and the positioned nucleosomes that flank CTCF binding sites. CTCF adjacent nucleosomes retained the correct positioning in regions completely devoid of CpG dinucleotides, suggesting that DNA methylation is not required for proper nucleosomes positioning. Conclusions: The biological mechanisms responsible for DNA methylation patterns outside of gene promoters remain poorly understood. We identified a significant genome-wide relationship between nucleosome organization and DNA methylation, which can be used to more accurately analyze and understand the epigenetic changes that accompany cancer and other diseases.


2018 ◽  
Vol 50 (12) ◽  
pp. 1051-1058 ◽  
Author(s):  
Samantha A. Brooks ◽  
John Stick ◽  
Ashley Braman ◽  
Katelyn Palermo ◽  
N. Edward Robinson ◽  
...  

Equine recurrent laryngeal neuropathy (RLN) is a bilateral mononeuropathy with an unknown etiology. In Thoroughbreds (TB), we previously demonstrated that the haplotype association for height (LCORL/NCAPG locus on ECA3, which affects body size) and RLN was coincident. In the present study, we performed a genome-wide association scan (GWAS) for RLN in 458 American Belgian Draft Horses, a breed fixed for the LCORL/NCAPG risk alelle. In this breed, RLN risk is associated with sexually dimorphic differences in height, and we identified a novel locus contributing to height in a sex-specific manner: MYPN (ECA1). Yet this specific locus contributes little to RLN risk, suggesting that other growth traits correlated to height may underlie the correlation to this disease. Controlling for height, we identified a locus on ECA15 contributing to RLN risk specifically in males. These results suggest that loci with sex-specific gene expression play an important role in altering growth traits impacting RLN etiology, but not necessarily adult height. These newly identified genes are promising targets for novel preventative and treatment strategies.


Epigenetics ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. 1079-1090 ◽  
Author(s):  
Sandrine Barbaux ◽  
Géraldine Gascoin-Lachambre ◽  
Christophe Buffat ◽  
Paul Monnier ◽  
Françoise Mondon ◽  
...  

1999 ◽  
Vol 73 (11) ◽  
pp. 9187-9195 ◽  
Author(s):  
Ralf R. Tönjes ◽  
Frank Czauderna ◽  
Reinhard Kurth

ABSTRACT The human genome harbors 25 to 50 proviral copies of the endogenous retrovirus type K (HERV-K), some of which code for the characteristic retroviral proteins Gag, Pol, and Env. For a genome-wide cloning approach of full-length and intact HERV-K proviruses, a human P1 gene library was screened with a gag-specific probe. Both HERV-K type 1 and 2 clones were isolated. Sixteen HERV-K type 2 proviral genomes were characterized by direct coupled in vitro transcription-in vitro translation assays to analyze the coding potential of isolatedgag, pol, and env amplicons from individual P1 clones. After determination of long terminal repeat (LTR) sequences and adjacent chromosomal integration sites by inverse PCR techniques, two HERV-K type 2 proviruses displaying long retroviral open reading frames (ORFs) were assigned to chromosomes 7 (C7) and 19 (C19) by using a human-rodent monochromosomal cell hybrid mapping panel. HERV-K(C7) shows an altered (YIDD-to-CIDD) motif in the reverse transcriptase domain. HERV-K(C19) is truncated in the 5′ LTR and harbors a defective protease gene due to a point mutation. Direct amplification of proviral structures from single chromosomes by using chromosomal flanking primers was performed by long PCR for HERV-K(C7) and HERV-K(C19) and for type 1 proviruses HERV-K10 and HERV-K18 from chromosomes 5 and 1, respectively. HERV-K18, in contrast to HERV-K10, bears no intact gag ORF and shows close homology to HERV-K/IDDMK1,222. In transfection experiments, HERV-K(C7) and HERV-K cDNA-based expression vectors yielded the proteins Gag and cORF whereas HERV-K10 vectors yielded Gag alone. The data suggest that the human genome does not contain an entire, intact proviral copy of HERV-K.


2013 ◽  
Author(s):  
Benjamin P. Berman ◽  
Yaping Liu ◽  
Theresa K. Kelly

Background: Nucleosome organization and DNA methylation are two mechanisms that are important for proper control of mammalian transcription, as well as epigenetic dysregulation associated with cancer. Whole-genome DNA methylation sequencing studies have found that methylation levels in the human genome show periodicities of approximately 190 bp, suggesting a genome-wide relationship between the two marks. A recent report (Chodavarapu et al., 2010) attributed this to higher methylation levels of DNA within nucleosomes. Here, we analyzed a number of published datasets and found a more compelling alternative explanation, namely that methylation levels are highest in linker regions between nucleosomes. Results: Reanalyzing the data from (Chodavarapu et al., 2010), we found that nucleosome-associated methylation could be strongly confounded by known sequence-related biases of the next-generation sequencing technologies. By accounting for these biases and using an unrelated nucleosome profiling technology, NOMe-seq, we found that genome-wide methylation was actually highest within linker regions occurring between nucleosomes in multi-nucleosome arrays. This effect was consistent among several methylation datasets generated independently using two unrelated methylation assays. Linker-associated methylation was most prominent within long Partially Methylated Domains (PMDs) and the positioned nucleosomes that flank CTCF binding sites. CTCF adjacent nucleosomes retained the correct positioning in regions completely devoid of CpG dinucleotides, suggesting that DNA methylation is not required for proper nucleosomes positioning. Conclusions: The biological mechanisms responsible for DNA methylation patterns outside of gene promoters remain poorly understood. We identified a significant genome-wide relationship between nucleosome organization and DNA methylation, which can be used to more accurately analyze and understand the epigenetic changes that accompany cancer and other diseases.


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