scholarly journals Decoding the 5′ nucleotide bias of PIWI-interacting RNAs

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Chad B. Stein ◽  
Pavol Genzor ◽  
Sanga Mitra ◽  
Alexandra R. Elchert ◽  
Jonathan J. Ipsaro ◽  
...  
Keyword(s):  
Nucleotide Bias

DeepCPP: a deep neural network based on nucleotide bias information and minimum distribution similarity feature selection for RNA coding potential prediction

2020 ◽  
Author(s):  
Yu Zhang ◽  
Cangzhi Jia ◽  
Melissa Jane Fullwood ◽  
Chee Keong Kwoh
Keyword(s):  
Neural Network ◽  
Feature Selection ◽  
Deep Neural Network ◽  
Feature Selection Method ◽  
Classification Problem ◽  
Open Reading Frames ◽  
Nucleotide Bias ◽  
Sequencing Technologies ◽  
Type Data ◽  
Coding Potential

Abstract The development of deep sequencing technologies has led to the discovery of novel transcripts. Many in silico methods have been developed to assess the coding potential of these transcripts to further investigate their functions. Existing methods perform well on distinguishing majority long noncoding RNAs (lncRNAs) and coding RNAs (mRNAs) but poorly on RNAs with small open reading frames (sORFs). Here, we present DeepCPP (deep neural network for coding potential prediction), a deep learning method for RNA coding potential prediction. Extensive evaluations on four previous datasets and six new datasets constructed in different species show that DeepCPP outperforms other state-of-the-art methods, especially on sORF type data, which overcomes the bottleneck of sORF mRNA identification by improving more than 4.31, 37.24 and 5.89% on its accuracy for newly discovered human, vertebrate and insect data, respectively. Additionally, we also revealed that discontinuous k-mer, and our newly proposed nucleotide bias and minimal distribution similarity feature selection method play crucial roles in this classification problem. Taken together, DeepCPP is an effective method for RNA coding potential prediction.

European bumblebees (Hymenoptera: Bombini)- phylogenetic relationships inferred from DNA sequences

2002 ◽  
Vol 33 (4) ◽  
pp. 361-386 ◽  
Author(s):  
Vest Pedersen
Keyword(s):  
Maximum Likelihood ◽  
Dna Sequences ◽  
Phylogenetic Trees ◽  
Phylogenetic Analyses ◽  
Mitochondrial Gene ◽  
Elongation Factor ◽  
Nuclear Gene ◽  
The Other ◽  
Elongation Factor 1Α ◽  
Nucleotide Bias

AbstractThe phylogenetics of 40 taxa of European bumblebees were analysed based on PCR amplified and direct sequenced DNA from one region of the mitochondrial gene Cytochrome Oxidase I (1046 bp) and for 26 taxa from two regions in the nuclear gene Elongation Factor 1α (1056 bp). The sequences were aligned to the corresponding sequences in the honey bee. Phylogenetic analyses based on parsimony, as well as maximum likelihood, indicate that the bumblebees can be separated into several well-supported clades. Most of the terminal clades correspond very well with the clades known from former phylogenetic analyses based on morphology and recognized as the subgenera: Mendacibombus, Confusibombus, Psithyrus, Thoracobombus, Megabombus, Rhodobombus, Kallobombus, Alpinobombus, Subterraneobombus, Alpigenobombus, Pyrobombus, Bombus and Melanobombus. All the cuckoo bumblebees form a well-supported clade, the subgenus Psithyrus, within the true bumblebees. All the analyses place Kallobombus as the most basal taxon in contradiction to former analyses. The other deeper nodes of the phylogenetic trees, which are weakly supported, deviate significantly from former published trees - especially the trees based on mtCO-I. Presumably, the reasons are that multiple hits and the strong bias of the bases A and T blur the relationships in the deepest part of the trees. Analyses of the region in mtCO-I show a very strong A+T bias (A+T= 75%), which also indicate preferences in the use of codons with A or T in third positions. In closely related entities, there is only a weak transversion bias (A+T). In the studied regions in EF 1-α, no nucleotide bias is observed. The observed differences in bases between the investigated taxa are relatively small and the gene is too conserved to solve all the questions that the analyses of the deeper nodes using mtCO-I raise.

scholarly journals The effect of nucleotide bias upon the composition and prediction of transmembrane helices

2008 ◽  
Vol 9 (3) ◽  
pp. 505-511 ◽  
Author(s):  
Timothy J. Stevens ◽  
Isaiah T. Arkin
Keyword(s):  
Transmembrane Helices ◽  
Nucleotide Bias

scholarly journals Exploitation of the Low Fidelity of Human Immunodeficiency Virus Type 1 (HIV-1) Reverse Transcriptase and the Nucleotide Composition Bias in the HIV-1 Genome To Alter the Drug Resistance Development of HIV

2001 ◽  
Vol 75 (13) ◽  
pp. 5772-5777 ◽  
Author(s):  
Jan Balzarini ◽  
Maria-José Camarasa ◽  
Maria-Jesus Pérez-Pérez ◽  
Ana San-Félix ◽  
Sonsoles Velázquez ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Resistance ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Resistance Development ◽  
Nucleotide Bias ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The RNA genome of the lentivirus human immunodeficiency virus type 1 (HIV-1) is significantly richer in adenine nucleotides than the statistically equal distribution of the four different nucleotides that is expected. This compositional bias may be due to the guanine-to-adenine (G→A) nucleotide hypermutation of the HIV genome, which has been explained by dCTP pool imbalances during reverse transcription. The adenine nucleotide bias together with the poor fidelity of HIV-1 reverse transcriptase markedly enhances the genetic variation of HIV and may be responsible for the rapid emergence of drug-resistant HIV-1 strains. We have now attempted to counteract the normal mutational pattern of HIV-1 in response to anti-HIV-1 drugs by altering the endogenous deoxynucleoside triphosphate pool ratios with antimetabolites in virus-infected cell cultures. We showed that administration of these antimetabolic compounds resulted in an altered drug resistance pattern due to the reversal of the predominant mutational flow of HIV (G→A) to an adenine-to-guanine (A→G) nucleotide pattern in the intact HIV-1-infected lymphocyte cultures. Forcing the virus to change its inherent nucleotide bias may lead to better control of viral drug resistance development.

scholarly journals Hierarchical analysis of mtDNA variation and the use of mtDNA for isopod (Crustacea: Peracarida: Isopoda) systematics

2001 ◽  
Vol 70 (1) ◽  
pp. 23-39 ◽  
Author(s):  
R. Wetzer
Keyword(s):  
Large Scale ◽  
Sequence Divergence ◽  
Molecular Study ◽  
Molecular Data ◽  
Hierarchical Analysis ◽  
Nucleotide Bias ◽  
Protein Coding ◽  
Phylogenetic Studies ◽  
Mtdna Variation ◽  
Hierarchical Levels

Carefully collected molecular data and rigorous analyses are revolutionizing today’s phylogenetic studies. Although molecular data have been used to estimate various invertebrate phylogenies for more than a decade, this study is the first survey of different regions of mitochondrial DNA in isopod crustaceans assessing sequence divergence and hence the usefulness of these regions to infer phylogeny at different hierarchical levels. I evaluate three loci from the mitochondrial genome (two ribosomal RNAs (12S, 16S) and one protein-coding (COI)) for their appropriateness in inferring isopod phylogeny at the suborder level and below. The patterns are similar for all three loci with the most speciose suborders of isopods also having the most divergent mitochondrial nucleotide sequences. Recommendations for designing an order- or suborder-level molecular study in previously unstudied groups of Crustacea would include: (1) collecting a minimum of two-four species or genera thought to be most divergent, (2) sampling across the group of interest as equally as possible in terms of taxonomic representation and the distribution of species, (3) surveying several genes, and (4) carrying out preliminary alignments, checking data for nucleotide bias, transition/ transversion ratios, and saturation levels before committing to a large-scale sequencing effort.

scholarly journals The HIV 5′ Gag Region Displays a Specific Nucleotide Bias Regulating Viral Splicing and Infectivity

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 997
Author(s):  
Bastian Grewe ◽  
Carolin Vogt ◽  
Theresa Horstkötter ◽  
Bettina Tippler ◽  
Han Xiao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Alternative Splicing ◽  
Nuclear Export ◽  
Rna Binding ◽  
Gc Content ◽  
Splice Donor Site ◽  
Viral Gene ◽  
Nucleotide Bias ◽  
Rna Sequence ◽  
Hiv Rna

Alternative splicing and the expression of intron-containing mRNAs is one hallmark of HIV gene expression. To facilitate the otherwise hampered nuclear export of non-fully processed mRNAs, HIV encodes the Rev protein, which recognizes its intronic response element and fuels the HIV RNAs into the CRM-1-dependent nuclear protein export pathway. Both alternative splicing and Rev-dependency are regulated by the primary HIV RNA sequence. Here, we show that these processes are extremely sensitive to sequence alterations in the 5’coding region of the HIV genomic RNA. Increasing the GC content by insertion of either GFP or silent mutations activates a cryptic splice donor site in gag, entirely deregulates the viral splicing pattern, and lowers infectivity. Interestingly, an adaptation of the inserted GFP sequence toward an HIV-like nucleotide bias reversed these phenotypes completely. Of note, the adaptation yielded completely different primary sequences although encoding the same amino acids. Thus, the phenotypes solely depend on the nucleotide composition of the two GFP versions. This is a strong indication of an HIV-specific mRNP code in the 5′ gag region wherein the primary RNA sequence bias creates motifs for RNA-binding proteins and controls the fate of the HIV-RNA in terms of viral gene expression and infectivity.

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