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RNA Sequencing Reveals Widespread Transcription of Natural Antisense RNAs in Entamoeba Species. Microorganisms 2022; 10:microorganisms10020396. [PMID: 35208849 PMCID: PMC8874941 DOI: 10.3390/microorganisms10020396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/26/2022] [Accepted: 02/05/2022] [Indexed: 11/17/2022] Open
Abstract
Entamoeba is a genus of Amoebozoa that includes the intestine-colonizing pathogenic species Entamoeba histolytica. To understand the basis of gene regulation in E. histolytica from an evolutionary perspective, we have profiled the transcriptomes of its closely related species E. dispar, E. moshkovskii and E. invadens. Genome-wide identification of transcription start sites (TSS) and polyadenylation sites (PAS) revealed the similarities and differences of their gene regulatory sequences. In particular, we found the widespread initiation of antisense transcription from within the gene coding sequences is a common feature among all Entamoeba species. Interestingly, we observed the enrichment of antisense transcription in genes involved in several processes that are common to species infecting the human intestine, e.g., the metabolism of phospholipids. These results suggest a potentially conserved and compact gene regulatory system in Entamoeba.
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Kaur D, Agrahari M, Bhattacharya A, Bhattacharya S. The non-LTR retrotransposons of Entamoeba histolytica: genomic organization and biology. Mol Genet Genomics 2022; 297:1-18. [PMID: 34999963 DOI: 10.1007/s00438-021-01843-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 11/26/2021] [Indexed: 11/24/2022]
Abstract
Genome sequence analysis of Entamoeba species revealed various classes of transposable elements. While E. histolytica and E. dispar are rich in non-long terminal repeat (LTR) retrotransposons, E. invadens contains predominantly DNA transposons. Non-LTR retrotransposons of E. histolytica constitute three families of long interspersed nuclear elements (LINEs), and their short, nonautonomous partners, SINEs. They occupy ~ 11% of the genome. The EhLINE1/EhSINE1 family is the most abundant and best studied. EhLINE1 is 4.8 kb, with two ORFs that encode functions needed for retrotransposition. ORF1 codes for the nucleic acid-binding protein, and ORF2 has domains for reverse transcriptase (RT) and endonuclease (EN). Most copies of EhLINEs lack complete ORFs. ORF1p is expressed constitutively, but ORF2p is not detected. Retrotransposition could be demonstrated upon ectopic over expression of ORF2p, showing that retrotransposition machinery is functional. The newly retrotransposed sequences showed a high degree of recombination. In transcriptomic analysis, RNA-Seq reads were mapped to individual EhLINE1 copies. Although full-length copies were transcribed, no full-length 4.8 kb transcripts were seen. Rather, sense transcripts mapped to ORF1, RT and EN domains. Intriguingly, there was strong antisense transcription almost exclusively from the RT domain. These unique features of EhLINE1 could serve to attenuate retrotransposition in E. histolytica.
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Yang N, Zhao B, Chen Y, D'Alessandro E, Chen C, Ji T, Wu X, Song C. Distinct Retrotransposon Evolution Profile in the Genome of Rabbit (Oryctolagus cuniculus). Genome Biol Evol 2021; 13:6322960. [PMID: 34270728 PMCID: PMC8346653 DOI: 10.1093/gbe/evab168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2021] [Indexed: 12/22/2022] Open
Abstract
Although the rabbit genome has already been annotated, it is mobilome remains largely unknown. Here, multiple pipelines were used to de novo mine and annotate the mobilome in rabbit. Four families and 19 subfamilies of LINE1s, two families and nine subfamilies of SINEs, and 12 ERV families were defined in rabbit based on sequence identity, structural organization, and phylogenetic tree. The analysis of insertion age and polymerase chain reaction suggests that a number of families are very young and may remain active, such as L1B, L1D, OcuSINEA, and OcuERV1. RepeatMasker annotation revealed a distinct transposable element landscape within the genome, with approximately two million copies of SINEs, representing the greatest proportion of the genome (19.61%), followed by LINEs (15.44%), and LTRs (4.11%), respectively, considerably different from most other mammal mobilomes except hedgehog and tree shrew, in which LINEs have the highest proportion. Furthermore, a very high rate of insertion polymorphisms (>85%) for the youngest subfamily (OcuSINEA1) was identified by polymerase chain reaction. The majority of retrotransposon insertions overlapped with protein-coding regions (>80%) and lncRNA (90%) genes. Genomic distribution bias was observed for retrotransposons, with those immediately upstream (-1 kb) and downstream (1 kb) of genes significantly depleted. Local GC content in 50-kb widows had significantly negative correlations with LINE (rs=-0.996) and LTR (rs=-0.829) insertions. The current study revealed a distinct mobilome landscape in rabbit, which will assist in the elucidation of the evolution of the genome of lagomorphs, and even other mammals.
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Affiliation(s)
- Naisu Yang
- College of Animal Science & Technology, Yangzhou University, Jiangsu, China
| | - Bohao Zhao
- College of Animal Science & Technology, Yangzhou University, Jiangsu, China
| | - Yang Chen
- College of Animal Science & Technology, Yangzhou University, Jiangsu, China
| | | | - Cai Chen
- College of Animal Science & Technology, Yangzhou University, Jiangsu, China
| | - Ting Ji
- College of Animal Science & Technology, Yangzhou University, Jiangsu, China
| | - Xinsheng Wu
- College of Animal Science & Technology, Yangzhou University, Jiangsu, China
| | - Chengyi Song
- College of Animal Science & Technology, Yangzhou University, Jiangsu, China
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Maurer-Alcalá XX, Nowacki M. Evolutionary origins and impacts of genome architecture in ciliates. Ann N Y Acad Sci 2019; 1447:110-118. [PMID: 31074010 PMCID: PMC6767857 DOI: 10.1111/nyas.14108] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 03/18/2019] [Accepted: 04/03/2019] [Indexed: 01/24/2023]
Abstract
Genome architecture is well diversified among eukaryotes in terms of size and content, with many being radically shaped by ancient and ongoing genome conflicts with transposable elements (e.g., the large transposon‐rich genomes common among plants). In ciliates, a group of microbial eukaryotes with distinct somatic and germ‐line genomes present in a single cell, the consequences of these genome conflicts are most apparent in their developmentally programmed genome rearrangements. This complicated developmental phenomenon has largely overshadowed and outpaced our understanding of how germ‐line and somatic genome architectures have influenced the evolutionary dynamism and potential in these taxa. In our review, we highlight three central concepts: how the evolution of atypical ciliate germ‐line genome architectures is linked to ancient genome conflicts; how the complex, epigenetically guided transformation of germline to soma during development can generate widespread genetic variation; and how these features, coupled with their unusual life cycle, have increased the rate of molecular evolution linked to genome architecture in these taxa.
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Affiliation(s)
| | - Mariusz Nowacki
- Institute of Cell Biology, University of Bern, Bern, Switzerland
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Maurer-Alcalá XX, Katz LA. An epigenetic toolkit allows for diverse genome architectures in eukaryotes. Curr Opin Genet Dev 2015; 35:93-9. [PMID: 26649755 DOI: 10.1016/j.gde.2015.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 02/04/2023]
Abstract
Genome architecture varies considerably among eukaryotes in terms of both size and structure (e.g. distribution of sequences within the genome, elimination of DNA during formation of somatic nuclei). The diversity in eukaryotic genome architectures and the dynamic processes are only possible due to the well-developed epigenetic toolkit, which probably existed in the Last Eukaryotic Common Ancestor (LECA). This toolkit may have arisen as a means of navigating the genomic conflict that arose from the expansion of transposable elements within the ancestral eukaryotic genome. This toolkit has been coopted to support the dynamic nature of genomes in lineages across the eukaryotic tree of life. Here we highlight how the changes in genome architecture in diverse eukaryotes are regulated by epigenetic processes, such as DNA elimination, genome rearrangements, and adaptive changes to genome architecture. The ability to epigenetically modify and regulate genomes has contributed greatly to the diversity of eukaryotes observed today.
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Affiliation(s)
- Xyrus X Maurer-Alcalá
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA; Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Laura A Katz
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA; Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA.
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Das K, Ganguly S. Evolutionary genomics and population structure of Entamoeba histolytica. Comput Struct Biotechnol J 2014; 12:26-33. [PMID: 25505504 PMCID: PMC4262060 DOI: 10.1016/j.csbj.2014.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 01/02/2023] Open
Abstract
Amoebiasis caused by the gastrointestinal parasite Entamoeba histolytica has diverse disease outcomes. Study of genome and evolution of this fascinating parasite will help us to understand the basis of its virulence and explain why, when and how it causes diseases. In this review, we have summarized current knowledge regarding evolutionary genomics of E. histolytica and discussed their association with parasite phenotypes and its differential pathogenic behavior. How genetic diversity reveals parasite population structure has also been discussed. Queries concerning their evolution and population structure which were required to be addressed have also been highlighted. This significantly large amount of genomic data will improve our knowledge about this pathogenic species of Entamoeba.
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Affiliation(s)
- Koushik Das
- Division of Parasitology, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme XM, Beliaghata, Kolkata 700010, India
| | - Sandipan Ganguly
- Division of Parasitology, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme XM, Beliaghata, Kolkata 700010, India
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Bradic M, Warring SD, Low V, Carlton JM. The Tc1/mariner transposable element family shapes genetic variation and gene expression in the protist Trichomonas vaginalis. Mob DNA 2014; 5:12. [PMID: 24834134 PMCID: PMC4021607 DOI: 10.1186/1759-8753-5-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 04/07/2014] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Trichomonas vaginalis is the most prevalent non-viral sexually transmitted parasite. Although the protist is presumed to reproduce asexually, 60% of its haploid genome contains transposable elements (TEs), known contributors to genome variability. The availability of a draft genome sequence and our collection of >200 global isolates of T. vaginalis facilitate the study and analysis of TE population dynamics and their contribution to genomic variability in this protist. RESULTS We present here a pilot study of a subset of class II Tc1/mariner TEs that belong to the T. vaginalis Tvmar1 family. We report the genetic structure of 19 Tvmar1 loci, their ability to encode a full-length transposase protein, and their insertion frequencies in 94 global isolates from seven regions of the world. While most of the Tvmar1 elements studied exhibited low insertion frequencies, two of the 19 loci (locus 1 and locus 9) show high insertion frequencies of 1.00 and 0.96, respectively. The genetic structuring of the global populations identified by principal component analysis (PCA) of the Tvmar1 loci is in general agreement with published data based on genotyping, showing that Tvmar1 polymorphisms are a robust indicator of T. vaginalis genetic history. Analysis of expression of 22 genes flanking 13 Tvmar1 loci indicated significantly altered expression of six of the genes next to five Tvmar1 insertions, suggesting that the insertions have functional implications for T. vaginalis gene expression. CONCLUSIONS Our study is the first in T. vaginalis to describe Tvmar1 population dynamics and its contribution to genetic variability of the parasite. We show that a majority of our studied Tvmar1 insertion loci exist at very low frequencies in the global population, and insertions are variable between geographical isolates. In addition, we observe that low frequency insertion is related to reduced or abolished expression of flanking genes. While low insertion frequencies might be expected, we identified two Tvmar1 insertion loci that are fixed across global populations. This observation indicates that Tvmar1 insertion may have differing impacts and fitness costs in the host genome and may play varying roles in the adaptive evolution of T. vaginalis.
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Affiliation(s)
- Martina Bradic
- Center for Genomics and Systems Biology, Department of Biology, New York University, 12 Waverly Place, New York, NY 10003, USA
| | - Sally D Warring
- Center for Genomics and Systems Biology, Department of Biology, New York University, 12 Waverly Place, New York, NY 10003, USA
| | - Vivien Low
- Center for Genomics and Systems Biology, Department of Biology, New York University, 12 Waverly Place, New York, NY 10003, USA
| | - Jane M Carlton
- Center for Genomics and Systems Biology, Department of Biology, New York University, 12 Waverly Place, New York, NY 10003, USA
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Kumari V, Iyer LR, Roy R, Bhargava V, Panda S, Paul J, Verweij JJ, Clark CG, Bhattacharya A, Bhattacharya S. Genomic distribution of SINEs in Entamoeba histolytica strains: implication for genotyping. BMC Genomics 2013; 14:432. [PMID: 23815468 PMCID: PMC3716655 DOI: 10.1186/1471-2164-14-432] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 06/20/2013] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND The major clinical manifestations of Entamoeba histolytica infection include amebic colitis and liver abscess. However the majority of infections remain asymptomatic. Earlier reports have shown that some E. histolytica isolates are more virulent than others, suggesting that virulence may be linked to genotype. Here we have looked at the genomic distribution of the retrotransposable short interspersed nuclear elements EhSINE1 and EhSINE2. Due to their mobile nature, some EhSINE copies may occupy different genomic locations among isolates of E. histolytica possibly affecting adjacent gene expression; this variability in location can be exploited to differentiate strains. RESULTS We have looked for EhSINE1- and EhSINE2-occupied loci in the genome sequence of Entamoeba histolytica HM-1:IMSS and searched for homologous loci in other strains to determine the insertion status of these elements. A total of 393 EhSINE1 and 119 EhSINE2 loci were analyzed in the available sequenced strains (Rahman, DS4-868, HM1:CA, KU48, KU50, KU27 and MS96-3382. Seventeen loci (13 EhSINE1 and 4 EhSINE2) were identified where a EhSINE1/EhSINE2 sequence was missing from the corresponding locus of other strains. Most of these loci were unoccupied in more than one strain. Some of the loci were analyzed experimentally for SINE occupancy using DNA from strain Rahman. These data helped to correctly assemble the nucleotide sequence at three loci in Rahman. SINE occupancy was also checked at these three loci in 7 other axenically cultivated E. histolytica strains and 16 clinical isolates. Each locus gave a single, specific amplicon with the primer sets used, making this a suitable method for strain typing. Based on presence/absence of SINE and amplification with locus-specific primers, the 23 strains could be divided into eleven genotypes. The results obtained by our method correlated with the data from other typing methods. We also report a bioinformatic analysis of EhSINE2 copies. CONCLUSIONS Our results reveal several loci with extensive polymorphism of SINE occupancy among different strains of E. histolytica and prove the principle that the genomic distribution of SINEs is a valid method for typing of E. histolytica strains.
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Affiliation(s)
- Vandana Kumari
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Lakshmi Rani Iyer
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Riti Roy
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Varsha Bhargava
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Suchita Panda
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Jaishree Paul
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Jaco J Verweij
- Laboratory for Medical Microbiology and Immunology, Laboratory for Clinical Pathology, St. Elisabeth Hospital, Tilburg, The Netherlands
| | - C Graham Clark
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Alok Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sudha Bhattacharya
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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In silico analysis of ubiquitin/ubiquitin-like modifiers and their conjugating enzymes in Entamoeba species. Parasitol Res 2012; 111:37-51. [DOI: 10.1007/s00436-011-2799-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 12/19/2011] [Indexed: 10/14/2022]
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