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Pagni S, Mills JD, Frankish A, Mudge JM, Sisodiya SM. Non-coding regulatory elements: Potential roles in disease and the case of epilepsy. Neuropathol Appl Neurobiol 2021; 48:e12775. [PMID: 34820881 DOI: 10.1111/nan.12775] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/04/2021] [Accepted: 11/16/2021] [Indexed: 12/27/2022]
Abstract
Non-coding DNA (ncDNA) refers to the portion of the genome that does not code for proteins and accounts for the greatest physical proportion of the human genome. ncDNA includes sequences that are transcribed into RNA molecules, such as ribosomal RNAs (rRNAs), microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and un-transcribed sequences that have regulatory functions, including gene promoters and enhancers. Variation in non-coding regions of the genome have an established role in human disease, with growing evidence from many areas, including several cancers, Parkinson's disease and autism. Here, we review the features and functions of the regulatory elements that are present in the non-coding genome and the role that these regions have in human disease. We then review the existing research in epilepsy and emphasise the potential value of further exploring non-coding regulatory elements in epilepsy. In addition, we outline the most widely used techniques for recognising regulatory elements throughout the genome, current methodologies for investigating variation and the main challenges associated with research in the field of non-coding DNA.
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Affiliation(s)
- Susanna Pagni
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Chalfont St Peter, UK
| | - James D Mills
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Chalfont St Peter, UK.,Amsterdam UMC, Department of (Neuro)Pathology, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Adam Frankish
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
| | - Jonathan M Mudge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Chalfont St Peter, UK
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Tinkel-Vernon H, Finkernagel S, Desposito F, Pittore C, Reynolds K, Sciorra L. Patient with a deletion of chromosome 21q and minimal phenotype. Am J Med Genet A 2003; 120A:142-3. [PMID: 12794708 DOI: 10.1002/ajmg.a.10210] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kurdyukov SG, Lebedev YB, Artamonova II, Gorodentseva TN, Batrak AV, Mamedov IZ, Azhikina TL, Legchilina SP, Efimenko IG, Gardiner K, Sverdlov ED. Full-sized HERV-K (HML-2) human endogenous retroviral LTR sequences on human chromosome 21: map locations and evolutionary history. Gene 2001; 273:51-61. [PMID: 11483360 DOI: 10.1016/s0378-1119(01)00570-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
One of the evolutionary mechanisms for acquisition of novel functional sequences can be domestication of exogenous retroviruses that have been integrated into the germ line. The whole genome mapping of such elements in various species could reveal differences in positions of the retroviral integration and suggest possible roles of these differences in speciation. Here, we describe the number, locations and sequence features of the human endogenous retrovirus HERV-K (HML-2) long terminal repeat (LTR) sequences on human chromosome 21. We show that their distribution along the chromosome is not only non-random but also roughly correlated with the gene density. Amplification of orthologous LTR sites from a number of primate genomes produced patterns of presence and absence for each LTR sequence and allowed determination of the phylogenetic ages and evolutionary order of appearance of individual LTRs. The identity level and phylogenetic age of the LTRs did not correlate with their map locations. Thus, despite the non-random distribution of LTRs, they have apparently been inserted randomly into the chromosome relative to each other. As evidenced in previous studies of chromosomes 19 and 22, this is a characteristic of HERV-K integration.
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Affiliation(s)
- S G Kurdyukov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, 16/10 Miklukho-Maklaya, Moscow, 117871, Russia
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Dierssen M, Martí E, Pucharcós C, Fotaki V, Altafaj X, Casas K, Solans A, Arbonés ML, Fillat C, Estivill X. Functional genomics of Down syndrome: a multidisciplinary approach. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2001:131-48. [PMID: 11771739 DOI: 10.1007/978-3-7091-6262-0_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The availability of the DNA sequence of human chromosome 21 (HSA21) is a landmark contribution that will have an immediate impact on the study of the role of specific genes to Down syndrome (DS). Trisomy 21, full or partial, is a major cause of mental retardation and other phenotypic abnormalities, collectively known as Down syndrome (DS), a disorder affecting 1 in 700 births. The identification of genes on HSA21 and the elucidation of the function of the proteins encoded by these genes have been a major challenge for the human genome project and for research in DS. Over 100 of the estimated 300-500 genes of HSA21 have been identified, but the function of most remains largely unknown. It is believed that the overexpression of an unknown number of HSA21 genes is directly or indirectly responsible for the mental retardation and the other clinical features of DS. For this reason, HSA21 genes that are expressed in tissues affected in DS patients are of special interest.
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Affiliation(s)
- M Dierssen
- Down Syndrome Research Group, Medical and Molecular Genetics Center-IRO, Hospital Duran i Reynals, L'Hospitalet de Llobregat, Barcelona, Spain
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Abstract
The recent completion of the DNA sequence of human chromosome 21 has provided the first look at the 225 genes that are candidates for involvement in Down syndrome (trisomy 21). A broad functional classification of these genes, their expression data and evolutionary conservation, and comparison with the gene content of the major mouse models of Down syndrome, suggest how the chromosome sequence may help in understanding the complex Down syndrome phenotype.
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Affiliation(s)
- K Gardiner
- Eleanor Roosevelt Institute, Gaylord Street, Denver, Colorado 80206-1210, USA.
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Slavov D, Hattori M, Sakaki Y, Rosenthal A, Shimizu N, Minoshima S, Kudoh J, Yaspo ML, Ramser J, Reinhardt R, Reimer C, Clancy K, Rynditch A, Gardiner K. Criteria for gene identification and features of genome organization: analysis of 6.5 Mb of DNA sequence from human chromosome 21. Gene 2000; 247:215-32. [PMID: 10773462 DOI: 10.1016/s0378-1119(00)00089-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To establish criteria for and the limitations of novel gene identification, to identify novel genes of potential relevance to Down Syndrome and to investigate features of genome organization, 6. 550kb. In total, 41 novel gene models were predicted, and for a subset of these, RT-PCR experiments helped to verify and refine the models, and were used to assess expression in early development and in adult brain regions of potential relevance to Down syndrome. Results suggest generally low and/or restricted patterns of expression, and also reveal examples of complex alternative processing, especially in brain, that may have important implications for regulation of protein function. Analysis of complete gene structures of the known genes identified a number of very large introns, a number of very short intergenic distances, and at least one potentially bi-directional promoter. At least 3/4 of known genes and 1/2 of predicted genes are associated with CpG islands. For novel genes, three cases of overlapping genes are predicted. Results of these analyses illustrate some of the complexities inherent in mammalian genome organization and some of the limitations of current sequence analysis technologies. They also doubled the number of potential genes within the region.
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Affiliation(s)
- D Slavov
- Eleanor Roosevelt Institute, 1899 Gaylord Street, Denver, CO 80206, USA
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Ruault M, Trichet V, Gimenez S, Boyle S, Gardiner K, Rolland M, Roizès G, De Sario A. Juxta-centromeric region of human chromosome 21 is enriched for pseudogenes and gene fragments. Gene 1999; 239:55-64. [PMID: 10571034 DOI: 10.1016/s0378-1119(99)00381-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A physical map including four pseudogenes and 10 gene fragments and spanning 500 kb in the juxta-centromeric region of the long arm of human chromosome 21 is presented. cDNA fragments isolated from a selected cDNA library were characterized and mapped to the 831B6 YAC and to two BAC contigs that cover 250 kb of the region. An 85 kb genomic sequence located in the proximal region of the map was analyzed for putative exons. Four pseudogenes were found, including psiIGSF3, psiEIF3, psiGCT-rel whose functional copies map to chromosome 1p13, chromosome 2 and chromosome 22q11, respectively. The TTLL1 pseudogene corresponds to a new gene whose functional copy maps to chromosome 22q13. Ten gene fragments represent novel sequences that have related sequences on different human chromosomes and show 97-100% nucleotide identity to chromosome 21. These may correspond to pseudogenes on chromosome 21 and to functional genes in other chromosomes. The 85 kb genomic sequence was analyzed also for GC content, CpG islands, and repetitive sequence distribution. A GC-poor L isochore spanning 40 kb from satellite 1 was observed in the most centromeric region, next to a GC-rich H isochore that is a candidate region for the presence of functional genes. The pericentric duplication of a 7.8 kb region that is derived from the 22q13 chromosome band is described. We showed that the juxta-centromeric region of human chromosome 21 is enriched for retrotransposed pseudogenes and gene fragments transferred by interchromosome duplications, but we do not rule out the possibility that the region harbors functional genes also.
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Affiliation(s)
- M Ruault
- Séquences Répétées et Centromères Humains, CNRS UPR 1142, Institut de Biologie, Montpellier, France
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Gardiner K. Saturation identification of coding sequences in genomic DNA. Methods Enzymol 1999; 303:144-61. [PMID: 10349644 DOI: 10.1016/s0076-6879(99)03012-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Affiliation(s)
- K Gardiner
- Eleanor Roosevelt Institute, Denver, Colorado 80206, USA
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Gardiner K. Human chromosome 21. Why 40 Mb? Ann N Y Acad Sci 1999; 870:362-8. [PMID: 10415499 DOI: 10.1111/j.1749-6632.1999.tb08904.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K Gardiner
- Eleanor Roosevelt Institute, Denver, Colorado 80206, USA.
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Tassone F, Villard L, Clancy K, Gardiner K. Structures, sequence characteristics, and synteny relationships of the transcription factor E4TF1, the splicing factor U2AF35 and the cystathionine beta synthetase genes from Fugu rubripes. Gene X 1999; 226:211-23. [PMID: 9931491 DOI: 10.1016/s0378-1119(98)00559-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
A cosmid containing the beta-amyloid precursor protein (APP) from Fugu rubripes has been completely sequenced. In addition to APP, the cosmid contains the E4TF1-60 transcription factor, the U2AF35 pre-mRNA splicing factor, and the cystathionine beta synthetase (CBS) gene. The human homologues of all four genes map to human chromosome 21 but are not clustered; APP and E4TF1-60 map within 21q21, whereas U2AF35 and CBS map approximately 20Mb distal in 21q22. 3. The protein sequences of the Fugu genes vary in their overall level of similarity to their mammalian homologues, but several regions of functional importance are almost identical. As expected, the intron/exon structures of the homologous pairs of genes are highly conserved, but there are significant differences in the compaction ratios. The introns of APP and E4TF1-60 are 49- and 24-fold smaller in Fugu than in human, and the intergenic distance is compressed at least 100-fold. For U2AF35 and CBS, the introns are compressed only five- to eightfold. These size differences were compared with those for a number of previously reported Fugu genes; in general, levels of compaction of Fugu genes are consistent with the isochore locations of the human homologues.
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Affiliation(s)
- F Tassone
- Eleanor Roosevelt Institute, 1899 Gaylord Street, Denver, CO 80206, USA
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Affiliation(s)
- M Angrist
- Department of Genetics, Case Western Reserve University, Cleveland, Ohio 44106-4955 USA.
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