scholarly journals Evolutionary dynamics of DIRS-like and Ngaro-like retrotransposons in Xenopus laevis and Xenopus tropicalis genomes

2021 ◽  
Author(s):  
Camilla Borges Gazolla ◽  
Adriana Ludwig ◽  
Joana Gama Moura ◽  
Daniel Pacheco Bruschi
Keyword(s):  
Molecular Structure ◽  
Xenopus Laevis ◽  
Phylogenetic Relationships ◽  
Transcriptional Activity ◽  
Evolutionary Dynamics ◽  
Open Reading Frames ◽  
Xenopus Tropicalis ◽  
Molecular Signatures ◽  
Reading Frames ◽  
High Diversity

Anuran genomes have a large number and diversity of transposable elements, but are little explored, mainly in relation to their molecular structure and evolutionary dynamics. Here, we investigated the retrotransposons containing tyrosine recombinase (YR) (order DIRS) in the genome of Xenopus tropicalis and Xenopus laevis. These anurans show 2n = 20 and the 2n = 36 karyotypes, respectively. They diverged about 48 million years ago (mya) and X. laevis had an allotetraploid origin (around 17-18 mya). Our investigation is based on the analysis of the molecular structure and the phylogenetic relationships of 95 DIRS families of Xenopus belonging to DIRS-like and Ngaro-like superfamilies. We were able to identify molecular signatures in the 5' and 3' non-coding terminal regions, preserved open reading frames (ORFs) and conserved domains that are specific to distinguish each superfamily. We recognize two ancient amplification waves of DIRS-like elements that occurred in the ancestor of both species and a higher density of the old/degenerate copies detected in the X. laevis. X. tropicalis showed more recent amplification waves estimated around 16 mya and 3.2 mya and corroborate with high diversity-level of families in this species and with transcriptional activity evidence. Ngaro-like elements presented less diversity and quantity in the genomes, although potentially active copies were also found. Our findings highlight a differential diversity-level and evolutionary dynamics of the YR retrotransposons in the diploid X. tropicalis and X. laevis species expanding our comprehension of the behavior of these elements in both genomes during the diversification process

scholarly journals Evolutionary dynamics of DIRS-like and Ngaro-like retrotransposons in Xenopus laevis and Xenopus tropicalis genomes

2021 ◽  
Author(s):  
Camilla Borges Gazolla ◽  
Adriana Ludwig ◽  
Joana de Moura Gama ◽  
Daniel Pacheco Bruschi
Keyword(s):  
Molecular Structure ◽  
Xenopus Laevis ◽  
Transposable Elements ◽  
Phylogenetic Relationships ◽  
Transcriptional Activity ◽  
Evolutionary Dynamics ◽  
Open Reading Frames ◽  
Xenopus Tropicalis ◽  
Molecular Signatures ◽  
Reading Frames

Abstract Anuran genomes have a large number and diversity of transposable elements, but are little explored, mainly in relation to their molecular structure and evolutionary dynamics. Here, we investigated the retrotransposons containing tyrosine recombinase (YR) (order DIRS) in the genome of Xenopus tropicalis and Xenopus laevis. These anurans show 2n = 20 and the 2n = 36 karyotypes, respectively. They diverged about 48 million years ago (mya) and X. laevis had an allotetraploid origin (around 17-18 mya). Our investigation is based on the analysis of the molecular structure and the phylogenetic relationships of 95 DIRS families of Xenopus belonging to DIRS-like and Ngaro-like superfamilies. We were able to identify molecular signatures in the 5' and 3' non-coding terminal regions, preserved open reading frames (ORFs) and conserved domains that are specific to distinguish each superfamily. We recognize two ancient amplification waves of DIRS-like elements that occurred in the ancestor of both species and a higher density of the old/degenerate copies detected in both subgenomes of X. laevis. More recent amplification waves are seen in X. tropicalis (less than 3.2 mya) and X. laevis (around 10 mya) corroborating with transcriptional activity evidence. All DIRS-like families were found in both X. laevis subgenomes, while a few were most represented in the L subgenome. Ngaro-like elements presented less diversity and quantity in X. tropicalis and X. laevis genomes, although potentially active copies were found in both species and this is consistent with a recent amplification wave seen in the evolutionary landscape. Our findings highlight a differential diversity-level and evolutionary dynamics of the YR retrotransposons in X. tropicalis and X. laevis species expanding our comprehension of the behavior of these elements in both genomes during the diversification process.

scholarly journals Oligonucleotide capture sequencing of the SARS-CoV-2 genome and subgenomic fragments from COVID-19 individuals

2020 ◽  
Author(s):  
Harsha Doddapaneni ◽  
Sara Javornik Cregeen ◽  
Richard Sucgang ◽  
Qingchang Meng ◽  
Xiang Qin ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Oligonucleotide Probe ◽  
Threshold Value ◽  
Open Reading Frames ◽  
Clinical Samples ◽  
Viral Loads ◽  
Full Length Genome ◽  
Probe Set ◽  
Reading Frames ◽  
Capture Sequencing

AbstractThe newly emerged and rapidly spreading SARS-CoV-2 causes coronavirus disease 2019 (COVID-19). To facilitate a deeper understanding of the viral biology we developed a capture sequencing methodology to generate SARS-CoV-2 genomic and transcriptome sequences from infected patients. We utilized an oligonucleotide probe-set representing the full-length genome to obtain both genomic and transcriptome (subgenomic open reading frames [ORFs]) sequences from 45 SARS-CoV-2 clinical samples with varying viral titers. For samples with higher viral loads (cycle threshold value under 33, based on the CDC qPCR assay) complete genomes were generated. Analysis of junction reads revealed regions of differential transcriptional activity and provided evidence of expression of ORF10. Heterogeneous allelic frequencies along the 20kb ORF1ab gene suggested the presence of a defective interfering viral RNA species subpopulation in one sample. The associated workflow is straightforward, and hybridization-based capture offers an effective and scalable approach for sequencing SARS-CoV-2 from patient samples.

scholarly journals Oligonucleotide capture sequencing of the SARS-CoV-2 genome and subgenomic fragments from COVID-19 individuals

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0244468
Author(s):  
Harsha Doddapaneni ◽  
Sara Javornik Cregeen ◽  
Richard Sucgang ◽  
Qingchang Meng ◽  
Xiang Qin ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Oligonucleotide Probe ◽  
Threshold Value ◽  
Open Reading Frames ◽  
Clinical Samples ◽  
Viral Loads ◽  
Full Length Genome ◽  
Probe Set ◽  
Reading Frames ◽  
Capture Sequencing

The newly emerged and rapidly spreading SARS-CoV-2 causes coronavirus disease 2019 (COVID-19). To facilitate a deeper understanding of the viral biology we developed a capture sequencing methodology to generate SARS-CoV-2 genomic and transcriptome sequences from infected patients. We utilized an oligonucleotide probe-set representing the full-length genome to obtain both genomic and transcriptome (subgenomic open reading frames [ORFs]) sequences from 45 SARS-CoV-2 clinical samples with varying viral titers. For samples with higher viral loads (cycle threshold value under 33, based on the CDC qPCR assay) complete genomes were generated. Analysis of junction reads revealed regions of differential transcriptional activity among samples. Mixed allelic frequencies along the 20kb ORF1ab gene in one sample, suggested the presence of a defective viral RNA species subpopulation maintained in mixture with functional RNA in one sample. The associated workflow is straightforward, and hybridization-based capture offers an effective and scalable approach for sequencing SARS-CoV-2 from patient samples.

scholarly journals Oligonucleotide Capture Sequencing of the SARS-CoV-2 Genome and Subgenomic Fragments from COVID-19 Individuals

2020 ◽  
Author(s):  
harshavardhan doddapaneni ◽  
Sara Javornik Cregeen ◽  
Richard Sucgang ◽  
Qingchang Meng ◽  
Xiang Qin ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Oligonucleotide Probe ◽  
Threshold Value ◽  
Open Reading Frames ◽  
Clinical Samples ◽  
Viral Loads ◽  
Full Length Genome ◽  
Probe Set ◽  
Reading Frames ◽  
Capture Sequencing

The newly emerged and rapidly spreading SARS-CoV-2 causes coronavirus disease 2019 (COVID-19). To facilitate a deeper understanding of the viral biology we developed a capture sequencing methodology to generate SARS-CoV-2 genomic and transcriptome sequences from infected patients. We utilized an oligonucleotide probe-set representing the full-length genome to obtain both genomic and transcriptome (subgenomic open reading frames [ORFs]) sequences from 45 SARS-CoV-2 clinical samples with varying viral titers. For samples with higher viral loads (cycle threshold value under 33, based on the CDC qPCR assay) complete genomes were generated. Analysis of junction reads revealed regions of differential transcriptional activity and provided evidence of expression of ORF10. Heterogeneous allelic frequencies along the 20kb ORF1ab gene suggested the presence of a defective interfering viral RNA species subpopulation in one sample. The associated workflow is straightforward, and hybridization-based capture offers an effective and scalable approach for sequencing SARS-CoV-2 from patient samples.

scholarly journals Composite transposable elements in the Xenopus laevis genome.

1989 ◽  
Vol 9 (7) ◽  
pp. 3018-3027 ◽  
Author(s):  
J E Garrett ◽  
D S Knutzon ◽  
D Carroll
Keyword(s):  
Xenopus Laevis ◽  
Transposable Elements ◽  
Repetitive Sequences ◽  
Open Reading Frames ◽  
The Other ◽  
Inverted Repeats ◽  
Terminal Inverted Repeats ◽  
Gag Proteins ◽  
High Degree ◽  
Reading Frames

Members of two related families of transposable elements, Tx1 and Tx2, were isolated from the genome of Xenopus laevis and characterized. In both families, two versions of the elements were found. The smaller version in each family (Tx1d and Tx2d) consisted largely of two types of 400-base-pair tandem internal repeats. These elements had discrete ends and short inverted terminal repeats characteristic of mobile DNAs that are presumed to move via DNA intermediates, e.g., Drosophila P and maize Ac elements. The longer versions (Tx1c and Tx2c) differed from Tx1d and Tx2d by the presence of a 6.9-kilobase-pair internal segment that included two long open reading frames (ORFs). ORF1 had one cysteine-plus-histidine-rich sequence of the type found in retroviral gag proteins. ORF2 showed more substantial homology to retroviral pol genes and particularly to the analogs of pol found in a subclass of mobile DNAs that are supposed retrotransposons, such as mammalian long interspersed repetitive sequences, Drosophila I factors, silkworm R1 elements, and trypanosome Ingi elements. Thus, the Tx1 elements present a paradox by exhibiting features of two classes of mobile DNAs that are thought to have very different modes of transposition. Two possible resolutions are considered: (i) the composite versions are actually made up of two independent elements, one of the retrotransposon class, which has a high degree of specificity for insertion into a target within the other, P-like element; and (ii) the composite elements are intact, autonomous mobile DNAs, in which the pol-like gene product collaborates with the terminal inverted repeats to cause transposition of the entire unit.

Evolutionary dynamics of introns and their open reading frames in the U7 region of the mitochondrial rnl gene in species of Ceratocystis

2013 ◽  
Vol 117 (11-12) ◽  
pp. 791-806 ◽  
Author(s):  
Jyothi Sethuraman ◽  
Shelly M. Rudski ◽  
Kari Wosnitza ◽  
Mohamed Hafez ◽  
Brent Guppy ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Open Reading Frames ◽  
Reading Frames

Composite transposable elements in the Xenopus laevis genome

1989 ◽  
Vol 9 (7) ◽  
pp. 3018-3027
Author(s):  
J E Garrett ◽  
D S Knutzon ◽  
D Carroll
Keyword(s):  
Xenopus Laevis ◽  
Transposable Elements ◽  
Repetitive Sequences ◽  
Open Reading Frames ◽  
The Other ◽  
Inverted Repeats ◽  
Terminal Inverted Repeats ◽  
Gag Proteins ◽  
High Degree ◽  
Reading Frames

Members of two related families of transposable elements, Tx1 and Tx2, were isolated from the genome of Xenopus laevis and characterized. In both families, two versions of the elements were found. The smaller version in each family (Tx1d and Tx2d) consisted largely of two types of 400-base-pair tandem internal repeats. These elements had discrete ends and short inverted terminal repeats characteristic of mobile DNAs that are presumed to move via DNA intermediates, e.g., Drosophila P and maize Ac elements. The longer versions (Tx1c and Tx2c) differed from Tx1d and Tx2d by the presence of a 6.9-kilobase-pair internal segment that included two long open reading frames (ORFs). ORF1 had one cysteine-plus-histidine-rich sequence of the type found in retroviral gag proteins. ORF2 showed more substantial homology to retroviral pol genes and particularly to the analogs of pol found in a subclass of mobile DNAs that are supposed retrotransposons, such as mammalian long interspersed repetitive sequences, Drosophila I factors, silkworm R1 elements, and trypanosome Ingi elements. Thus, the Tx1 elements present a paradox by exhibiting features of two classes of mobile DNAs that are thought to have very different modes of transposition. Two possible resolutions are considered: (i) the composite versions are actually made up of two independent elements, one of the retrotransposon class, which has a high degree of specificity for insertion into a target within the other, P-like element; and (ii) the composite elements are intact, autonomous mobile DNAs, in which the pol-like gene product collaborates with the terminal inverted repeats to cause transposition of the entire unit.

Sign in / Sign up

Export Citation Format

Share Document