Designing siRNA that distinguish between genes that differ by a single nucleotide
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE5291 | GEO | 2006/08/04
SECONDARY ACCESSION(S): PRJNA96413
REPOSITORIES: GEO
Similar Datasets
Project description: Not available
| S-EPMC1560399 | biostudies-literature
Project description:The use of DNA microarrays to identify nucleotide variation is almost 20 years old. A variety of improvements in probe design and experimental conditions have brought this technology to the point that single-nucleotide differences can be efficiently detected in unmixed samples, although developing reliable methods for detection of mixed sequences (e.g. heterozygotes) remains challenging. Surprisingly, a comprehensive study of the probe design parameters and experimental conditions that optimize discrimination of single nucleotide polymorphisms (SNPs) has yet to be reported, so the limits of this technology remain uncertain. By targeting 24,549 SNPs that differ between two Saccharomyces cerevisiae strains, we studied the effect of SNPs on hybridization efficiency to DNA microarray probes of different lengths under different hybridization conditions. We found that the critical parameter for optimization of sequence discrimination is the relationship between probe melting temperature (Tm) and the temperature at which the hybridization reaction is performed. This relationship can be exploited through the design of microarrays containing probes of equal Tm by varying the length of probes. We demonstrate that using such a microarray we detect >90% homozygous SNPs and >80% heterozygous SNPs using the SNPScanner algorithm. The optimized design and experimental parameters determined in this study should guide DNA microarray designs for applications that require sequence discrimination such as mutation detection, genotyping of unmixed and mixed samples and allele-specific gene expression. Moreover, designing microarray probes with optimized sensitivity to mismatches should increase the accuracy of standard microarray applications such as copy number variation detection and gene expression analysis. Keyword(s): MutationDetection_CGH Comparison of polymorphic vs non-polymorphic genomes when hybridrized to short probe microarrays
2010-05-18 | E-GEOD-19319 | biostudies-arrayexpress
Project description:The use of DNA microarrays to identify nucleotide variation is almost 20 years old. A variety of improvements in probe design and experimental conditions have brought this technology to the point that single-nucleotide differences can be efficiently detected in unmixed samples, although developing reliable methods for detection of mixed sequences (e.g. heterozygotes) remains challenging. Surprisingly, a comprehensive study of the probe design parameters and experimental conditions that optimize discrimination of single nucleotide polymorphisms (SNPs) has yet to be reported, so the limits of this technology remain uncertain. By targeting 24,549 SNPs that differ between two Saccharomyces cerevisiae strains, we studied the effect of SNPs on hybridization efficiency to DNA microarray probes of different lengths under different hybridization conditions. We found that the critical parameter for optimization of sequence discrimination is the relationship between probe melting temperature (Tm) and the temperature at which the hybridization reaction is performed. This relationship can be exploited through the design of microarrays containing probes of equal Tm by varying the length of probes. We demonstrate that using such a microarray we detect >90% homozygous SNPs and >80% heterozygous SNPs using the SNPScanner algorithm. The optimized design and experimental parameters determined in this study should guide DNA microarray designs for applications that require sequence discrimination such as mutation detection, genotyping of unmixed and mixed samples and allele-specific gene expression. Moreover, designing microarray probes with optimized sensitivity to mismatches should increase the accuracy of standard microarray applications such as copy number variation detection and gene expression analysis. Keyword(s): MutationDetection_CGH
2009-12-10 | GSE19319 | GEO
Project description:Members of the ribonuclease (RNase) III family regulate gene expression by processing double-stranded (ds) RNA. The founding member of the family, Escherichia coli (Ec) RNase III, is the most comprehensively studied and its E38A mutant (EcE38A) is an economical reagent for the preparation of small interfering (si) RNA cocktails. Previously, it was shown that EcRNase III recognizes dsRNA with little specificity and that EcE38A mainly produces 23-nucleotide (nt) siRNAs. To characterize substrate specificity and product size, we performed in vitro cleavage of dsRNAs by bacterial RNase IIIs and delineated the cleavage products by next generation sequencing. Surprisingly, we found that RNase III cleaves dsRNA at preferred sites and most siRNAs produced by EcE38A are 22 nt long. We eliminated the sequence specificity of EcE38A through the introduction of additional mutations, thereby creating a reagent that is ideally suited for producing heterogeneous siRNA cocktails to be used in gene silencing studies.
2019-05-26 | GSE120052 | GEO
Project description:Interventions: Endoscopic examinations of mucosal membrane using three-dimensional optical coherence tomography probe.
Primary outcome(s): Discrimination ability of mucosal membrane structure. Discrimination ability of cancer tissue.
Study Design: Single arm Non-randomized
| 2618337 | ecrin-mdr-crc
Project description:We tested the ability of trans siRNAs to establish a silent allele of endogenous ade6+ or an ade6+ transgene inserted within euchromatic loci. We found that a silent ade6-OFF epi-allele that grows red on low adenine medium could be established in several mutant backgrounds (mlo3∆, leo1∆) in the presence of ectopic siRNAs. Furthermore, we found that the silent ade6-OFF epi-allele could be meiotically inherited to wildtype progeny lacking the establishing mutation or ectopic siRNAs. Here, we sequenced genome-wide small RNAs and found widespread generation of secondary siRNAs at genes surrounding the ade6-OFF locus in cells expressing the ectopic siRNAs source cen::ade6. In wildtype meiotic progeny lacking the driver cen::ade6 siRNAs, we observed establishment of a local siRNA producing locus at genes adjacent to the endogenous ade6-OFF or at a kanMX-ade6-OFF transgene inserted within euchromatic loci. In contrast, spreading of secondary siRNAs was limited or nonexistent in ade6-ON cells. Finally, we found that spreading of secondary siRNAs at the endogenous ade6 locus was limited when an ade6 hairpin construct served as the ectopic siRNA driver locus instead of cen::ade6.
2018-04-26 | GSE111858 | GEO
Project description:Allele-specific circular chromosome conformation capture sequencing (4C-seq) using the single nucleotide polymorphism rs2836411 as a bait was performed in two cell types: human umibilical vein endothelial cells (HUVECs) and human aortic smooth muscle cells (HASMCs).
2019-10-11 | GSE137288 | GEO
Project description:Establishing the functional roles of genetic variants remains a significant challenge in the post-genomic era. Here, we present a method, allele-specific alternative mRNA processing (ASARP), to identify genetically influenced mRNA processing events using transcriptome sequencing (RNA-Seq) data. The method examines RNA-Seq data at both single nucleotide and whole-gene/isoform levels to identify allele-specific expression (ASE) and existence of allele-specific regulation of mRNA processing. We applied the methods to data obtained from the human glioblastoma cell line U87MG and primary breast cancer tissues and found that 26M-bM-^@M-^S45% of all genes with sufficient read coverage demonstrated ASE, with significant overlap between the two cell types. Our methods predicted potential mechanisms underlying ASE due to regulations affecting either whole-gene-level expression or alternative mRNA processing, including alternative splicing, alternative polyadenylation and alternative transcriptional initiation. Allele-specific alternative splicing and alternative polyadenylation may explain ASE in hundreds of genes in each cell type. Reporter studies following these predictions identified the causal single nucleotide variants (SNVs) for several allele-specific alternative splicing events. Finally, many genes identified in our study were also reported as disease/phenotype-associated genes in genome-wide association studies. Future applications of our approach may provide ample insights for a better understanding of the genetic basis of gene regulation underlying phenotypic diversity and disease mechanisms. Examine allele-specific gene expression and alternative RNA processing in U87MG cell line
2012-03-29 | E-GEOD-29738 | biostudies-arrayexpress
Project description:We tested the ability of trans siRNAs to establish a silent allele of endogenous ade6+ or an ade6+ transgene inserted within euchromatic loci. We found that a silent ade6-OFF epi-allele that grows red on low adenine medium could be established in several mutant backgrounds (mlo3∆, leo1∆) in the presence of ectopic siRNAs. Furthermore, we found that the silent ade6-OFF epi-allele could be meiotically inherited to wildtype progeny lacking the establishing mutation or ectopic siRNAs. Here, we sequenced genome-wide DNA associated with conserved heterochromatin markers and found that silencing of the endogenous ade6 locus correlates with increased spreading of H3K9me2 and H3K9me3. Additionally, heterochromatin domains established with cen::ade6 as the ectopic siRNA-producing locus were associated with significantly more spreading of H3K9me2 and H3K9me3 than those established using an ade6 hairpin as the driver siRNA-producing locus.
2018-04-26 | GSE111851 | GEO
Project description:Establishing the functional roles of genetic variants remains a significant challenge in the post-genomic era. Here, we present a method, allele-specific alternative mRNA processing (ASARP), to identify genetically influenced mRNA processing events using transcriptome sequencing (RNA-Seq) data. The method examines RNA-Seq data at both single nucleotide and whole-gene/isoform levels to identify allele-specific expression (ASE) and existence of allele-specific regulation of mRNA processing. We applied the methods to data obtained from the human glioblastoma cell line U87MG and primary breast cancer tissues and found that 26–45% of all genes with sufficient read coverage demonstrated ASE, with significant overlap between the two cell types. Our methods predicted potential mechanisms underlying ASE due to regulations affecting either whole-gene-level expression or alternative mRNA processing, including alternative splicing, alternative polyadenylation and alternative transcriptional initiation. Allele-specific alternative splicing and alternative polyadenylation may explain ASE in hundreds of genes in each cell type. Reporter studies following these predictions identified the causal single nucleotide variants (SNVs) for several allele-specific alternative splicing events. Finally, many genes identified in our study were also reported as disease/phenotype-associated genes in genome-wide association studies. Future applications of our approach may provide ample insights for a better understanding of the genetic basis of gene regulation underlying phenotypic diversity and disease mechanisms.
2012-03-30 | GSE29738 | GEO