Long-read cDNA sequencing identifies functional pseudogenes in the human transcriptome
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE160383 | GEO | 2021/04/26
REPOSITORIES: GEO
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Project description:Human genome encodes >14,000 pseudogenes that are evolutionary relics and have long been considered as nonfunctional genomic elements. Emerging evidence suggests that pseudogene can exert important regulatory function. However, function of most pseudogenes remains unknown. To fill this gap, we developed an integrated computational pipeline and performed to date the first set of pseudogene-focused CRISPRi screens in human cells. Our screens identified >100 pseudogenes that are important for cell fitness, with a more cell-type specific function compared to parent genes. In addition, we discovered a cancer-testis unitary pseudogene MGAT4EP that interacts with FOXA1, a key regulator in luminal A breast cancer.
2021-08-01 | GSE155510 | GEO
Project description:Pseudogenes, non-coding homologs of protein-coding genes, were once considered non-functional evolutional relics. Recent studies have shown that pseudogene transcripts can regulate their parental transcripts by sequestering shared microRNAs, thus acting as competing endogenous RNAs (ceRNAs). In this study, we utilize an unbiased screen to identify the ferritin heavy chain 1 (FTH1) transcript and multiple FTH1 pseudogenes as targets of several oncogenic miRNAs in prostate cancer. We characterize the critical role of this FTH1 gene:pseudogene:microRNA network in regulating tumorigenesis in prostate cancer, and show that impairing microRNA binding and subsequent ceRNA crosstalk results in complete phenotype rescue. Our results also demonstrate that pseudogenes are able to regulate intracellular iron levels, which are crucial for multiple physiological and pathophysiological processes. In summary, we describe a novel and extensive gene:pseudogene ceRNA network comprising multiple microRNAs and multiple pseudogenes derived from a single parental gene, which regulates iron storage and tumorigenesis in prostate cancer.
2017-07-26 | GSE101837 | GEO
Project description:Background: Canonical Nonsense Mediated Decay (NMD) is an important splicing-dependent process for mRNA surveillance in mammals. However, processed pseudogenes are not able to trigger NMD due to their lack of introns. It is largely unknown whether they have evolved other surveillance mechanisms. Results: Here, we find that the RNAs of pseudogenes, especially processed pseudogenes, have dramatically higher m6A levels than their cognate protein-coding genes, associated with de novo m6A peaks and motifs in human cells. Furthermore, pseudogenes have rapidly accumulated m6A motifs during evolution. The m6A sites of pseudogenes are evolutionarily younger than neutral sites and their m6A levels are increasing, supporting the idea that m6A on the RNAs of pseudogenes is under positive selection. We then find that the m6A RNA modification of processed, rather than unprocessed, pseudogenes promotes cytosolic RNA degradation and attenuates interference with the RNAs of their cognate protein-coding genes. We experimentally validate the m6A RNA modification of two processed pseudogenes, DSTNP2 and NAP1L4P1, which promotes the RNA degradation of both pseudogenes and their cognate protein-coding genes DSTN and NAP1L4. In addition, the m6A of DSTNP2 regulation of DSTN is partially dependent on the miRNA miR-362-5p. Conclusions: Our discovery reveals a novel evolutionary role of m6A RNA modification in cleaning up the unnecessary processed pseudogene transcripts to attenuate their interfering with the regulatory network of proteincoding genes.
2021-05-27 | GSE172219 | GEO
Project description:Pseudogenes are defined as regions of the genome that resemble functional genes but contain disabling mutations and lack regulatory elements needed for transcription or translation. They are excellent markers for genome evolution and are emerging as crucial regulators of the development and disease, especially cancer. However, systematic functional characterization and evolution of pseudogene remain largely unexplored. In particular, the contribution of pseudogene to organ development is still unknown. Meanwhile, studies of pseudogene transcription, which is the first step for generating functional RNA, is precluded by the limited capacity of short-read sequencing. To address these issues, we systematically inferred the origin time and characterized the evolution pattern of pseudogenes. We leveraged PacBio full-length sequencing in combination with deep Illumina data as well as public developmental time-course RNA-seq, we dramatically expanded the analyzed samples and profiled genome-wide pseudogene expression paradigm. Additionally, we prioritized functional pseudogenes at multiple regulatory layers and determined their implications in disease and cancer biology.
2022-02-18 | GSE176018 | GEO
Project description:<p>In this study, we describe a systematic analysis of pseudogene 'transcription' from an RNA-Seq resource of 293 samples, from 13 cancer and normal tissue types. We observed a highly prevalent, genome-wide expression of pseudogenes that could be categorized as universally expressed or lineage- and/or cancer-specific. We also explored disease subtype specificity and functions of selected expressed pseudogenes. We provide evidence that transcribed pseudogenes are a significant contributor to the transcriptional landscape of cells and are positioned to play significant roles in cellular differentiation and cancer progression. Our work provides a transcriptome resource that enables high-throughput analyses of pseudogene expression.</p>
| phs000525 | dbGaP
Project description:Approximately half of M. lepraeâ??s transcriptome consists of inactive gene products. This has an impact on overall energy and resource consumption without potential benefit to this organism. However, multiple translational â??silencingâ?? mechanisms are present, reducing additional energy and resource expenditure required for protein production from these transcripts. The Mycobacterium leprae genome has less than 50% coding capacity and 1,133 pseudogenes. Preliminary evidence suggests that some pseudogenes are expressed. Therefore, defining pseudogene transcriptional and translational potentials should increase our understanding of their impact on M. leprae physiology. To address this, M. leprae was purified from the granulomatous hind footpad tissue of four individual nu/nu nude mice six months post-infection. M. leprae whole genome DNA microarrays representing the 1,614 annotated ORFs and 1,133 identified pseudogenes, were obtained from the Leprosy Research Support and Maintenance of an Armadillo Colony Post-Genome Era, Part I: Leprosy Research Support Contract (NO1 AI-25469) at Colorado State University. To validate 20% of genes positive by microarray analysis, RT-PCR was performed. Results of this study Gene expression analysis identified transcripts from 49% of all M. leprae genes including 57% of all ORFs and 43% of all pseudogenes in the genome. Pseudogenes were randomly distributed throughout the chromosome. Factors resulting in pseudogene transcription included: 1) co-orientation of transcribed pseudogenes with transcribed ORFs within or exclusive of operon-like structures; 2) the paucity of intrinsic stem-loop transcriptional terminators between transcribed ORFs and downstream pseudogenes; and 3) predicted pseudogene promoters. Mechanisms for translational silencing of pseudogene transcripts included the lack of both translational start codons and strong Shine-Dalgarno sequences. Transcribed pseudogenes also contained multiple in-frame stop codons and high Ka/Ks ratios, compared to that of homologs in M. tuberculosis and ORFs in M. leprae. A pseudogene transcript containing an active promoter, strong SD site, a start codon, but containing two in frame stop codons yielded a protein product when expressed in E. coli. Approximately half of M. leprae's transcriptome consists of inactive gene products consuming energy and resources without potential benefit to M. leprae. Presently it is unclear what additional detrimental affect(s) this large number of inactive mRNAs has on the functional capability of this organism. Translation of these pseudogenes may play an important role in overall energy consumption and resultant pathophysiological characteristics of M. leprae. However, this study also demonstrated that multiple translational silencing mechanisms are present, reducing additional energy and resource expenditure required for protein production from the vast majority of these transcripts. The overall design of this study was to identify the transcriptome of M. leprae in the granulomatous tissue of the mouse hind foot pad 6 months post infection.
2010-06-24 | E-GEOD-17191 | biostudies-arrayexpress
Project description:Approximately half of M. leprae’s transcriptome consists of inactive gene products. This has an impact on overall energy and resource consumption without potential benefit to this organism. However, multiple translational ‘silencing’ mechanisms are present, reducing additional energy and resource expenditure required for protein production from these transcripts. The Mycobacterium leprae genome has less than 50% coding capacity and 1,133 pseudogenes. Preliminary evidence suggests that some pseudogenes are expressed. Therefore, defining pseudogene transcriptional and translational potentials should increase our understanding of their impact on M. leprae physiology. To address this, M. leprae was purified from the granulomatous hind footpad tissue of four individual nu/nu nude mice six months post-infection. M. leprae whole genome DNA microarrays representing the 1,614 annotated ORFs and 1,133 identified pseudogenes, were obtained from the Leprosy Research Support and Maintenance of an Armadillo Colony Post-Genome Era, Part I: Leprosy Research Support Contract (NO1 AI-25469) at Colorado State University. To validate 20% of genes positive by microarray analysis, RT-PCR was performed. Results of this study Gene expression analysis identified transcripts from 49% of all M. leprae genes including 57% of all ORFs and 43% of all pseudogenes in the genome. Pseudogenes were randomly distributed throughout the chromosome. Factors resulting in pseudogene transcription included: 1) co-orientation of transcribed pseudogenes with transcribed ORFs within or exclusive of operon-like structures; 2) the paucity of intrinsic stem-loop transcriptional terminators between transcribed ORFs and downstream pseudogenes; and 3) predicted pseudogene promoters. Mechanisms for translational silencing of pseudogene transcripts included the lack of both translational start codons and strong Shine-Dalgarno sequences. Transcribed pseudogenes also contained multiple in-frame stop codons and high Ka/Ks ratios, compared to that of homologs in M. tuberculosis and ORFs in M. leprae. A pseudogene transcript containing an active promoter, strong SD site, a start codon, but containing two in frame stop codons yielded a protein product when expressed in E. coli. Approximately half of M. leprae's transcriptome consists of inactive gene products consuming energy and resources without potential benefit to M. leprae. Presently it is unclear what additional detrimental affect(s) this large number of inactive mRNAs has on the functional capability of this organism. Translation of these pseudogenes may play an important role in overall energy consumption and resultant pathophysiological characteristics of M. leprae. However, this study also demonstrated that multiple translational silencing mechanisms are present, reducing additional energy and resource expenditure required for protein production from the vast majority of these transcripts.
2009-07-21 | GSE17191 | GEO
Project description:<p>In this study, we describe a systematic analysis of pseudogene 'transcription' from an RNA-Seq resource of 293 samples, from 13 cancer and normal tissue types. We observed a highly prevalent, genome-wide expression of pseudogenes that could be categorized as universally expressed or lineage- and/or cancer-specific. We also explored disease subtype specificity and functions of selected expressed pseudogenes. We provide evidence that transcribed pseudogenes are a significant contributor to the transcriptional landscape of cells and are positioned to play significant roles in cellular differentiation and cancer progression. Our work provides a transcriptome resource that enables high-throughput analyses of pseudogene expression.</p>
| phs000525.v1.p1 | EGA
Project description:Genomic sequences with high sequence similarity, such as parent-pseudogene pairs, cause short sequencing reads to align to multiple locations, thus complicating genomic analyses. However, their impact on transcriptomic analyses, including the estimation of gene expression and transcript annotation, has been less studied. Here, we investigated the impact of pseudogenes on transcriptomic analyses.
2022-10-15 | GSE215459 | GEO
Project description:We aim to comprehensively characterize the small RNA population in oocytes Pseudogenes populate the mammalian genome as remnants of artifactual incorporation of coding mRNAs into transposon pathways 1. Here, we show that a subset of pseudogenes generates endogenous small interfering RNAs (endo-siRNAs) in mouse oocytes. In these cases, endo-siRNAs are often processed from double-stranded RNAs formed by hybridization of spliced transcripts from protein coding genes to antisense transcripts from homologous pseudogenes. In at least one case, an inverted repeat pseudogene gives rise to abundant small RNAs directly. A second class of endo-siRNAs may enforce repression of mobile genetic elements, acting in concert with piwi-interacting RNAs (piRNAs). Loss of Dicer increases expression of endo-siRNA targets, demonstrating the regulatory activity of these small RNAs. Our findings provide a function for pseudogenes in regulating gene expression via the RNAi pathway and may, in part, explain the evolutionary pressure to conserve Argonaute-mediated catalysis in mammals. Keywords: small RNAs profile
2008-03-28 | GSE10364 | GEO