Non-coding antisense transcription detected by conventional and single-stranded cDNA microarray
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE7860 | GEO | 2007/09/01
SECONDARY ACCESSION(S): PRJNA99997
REPOSITORIES: GEO
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Project description:Recent bioinformatic studies revealed that many mammalian protein-coding genes also transcribe their complementary strands. This phenomenon raises questions regarding the validity of data obtained from double-stranded cDNA microarrays since hybridization to both strands may occur. To analyze experimentally the incidence of antisense transcription in human cells and to estimate their influence on protein coding expression patterns obtained by double-stranded microarrays, we profiled transcription with sense and antisense independently by using strand-specific cDNA microarrays. We modeled an experimental design typically used for tumor classification studies. We performed hybridizations using direct-labeled randomly primed total RNA extracted from eight breast-cancer cell lines and one derived from normal breast epithelium against Universal Human Reference RNA as a common reference following standard protocols.
2007-09-01 | E-GEOD-7860 | biostudies-arrayexpress
Project description:Non-coding antisense transcription detected by conventional and single-stranded cDNA microarray
| PRJNA99997 | ENA
Project description:Background: With lower manufacturing cost, high spot density, and flexible probe design, genomic tiling microarrays are ideal for comprehensive transcriptome studies. Typically, transcriptome profiling using microarrays involves reverse transcription, which converts RNA to cDNA. The cDNA is then labeled and hybridized to the probes on the arrays, thus the RNA signals are detected indirectly. Reverse transcription is known to generate artifactual cDNA, in particular the synthesis of second-strand cDNA, leading to false discovery of antisense RNA. To address this issue, we have developed an effective method using RNA that is directly labeled, thus by-passing the cDNA generation. This paper describes the development of this method and its application to mapping transcriptome profiles. Results: RNA extracted from laboratory cultures of Porphyromonas gingivalis was fluorescently labeled with an alkylation reagent and hybridized directly to probes on genomic tiling microarrays specifically designed for this periodontal pathogen. The generated transcriptome profile was strand-specific and produced signals close to background level in most antisense regions of the genome. In contrast, high levels of signal were detected in the antisense regions when the hybridization was done with cDNA. In addition, five antisense areas were tested with independent strand-specific RT-PCR and none to negligible amplification was detected, indicating that the strong antisense cDNA signals were artifacts. Conclusions: An efficient method was developed for mapping transcriptome profiles specific to both coding strands of a bacterial genome. This method chemically labels and uses extracted RNA directly in microarray hybridization. The generated transcriptome profile was free of cDNA artifactual signals. In addition, this method requires fewer processing steps and is more sensitive in detecting small amount of RNA compared to end-labeling methods due to the incorporation of more fluorescent molecules per RNA fragment.
2010-12-09 | GSE25876 | GEO
Project description:Small non-coding RNA biogenesis typically involves cleavage of structured precursors by RNase III-like endonucleases. However, guide RNAs that direct U-insertion/deletion mRNA editing in mitochondria of trypanosomes maintain 5′ triphosphate characteristic of transcription start site and possess U-tail indicative of 3′ processing and uridylation. Here, we identified a protein complex composed of RET1 TUTase and 3′-5′ DSS1 exonuclease, and three additional subunits. This complex, termed mitochondrial 3′ processome (MPsome), is responsible for primary uridylation of ~800-nt gRNA precursors, their processive degradation to a mature length of 50-60 nt, and secondary U-tail addition. Both strands of gRNA gene are transcribed giving rise to sense and antisense precursors of similar size. Head-to-head hybridization of these transcripts blocks symmetrical 3′-5′ degradation at the fixed distance from the double-stranded region. Together, our findings suggest a model in which gRNA is derived from the 5′ extremity of a primary molecule by uridylation-induced, antisense transcription-controlled exonucleolytic degradation.
2016-02-08 | GSE71292 | GEO
Project description:We examined the biogenesis of mRNA-derived endogenous short-interfering RNAs (endo-siRNAs) in the disease vector mosquito, Aedes aegypti. Under standard conditions, mRNA-derived endo-siRNAs were produced from the bidirectional transcription of tail-tail overlapping gene pairs. Upon infection with the alphavirus, Sindbis virus (SINV), another class of mRNA-derived endo-siRNAs was observed. Genes producing SINV-induced endo-siRNAs were not enriched for overlapping partners or nearby genes, but were enriched for transcripts with long 3'UTRs. Endo-siRNAs from this class derived uniformly from the entire length of the target transcript, and were found to regulate the transcript levels of the genes from which they were derived. Strand-specific qPCR experiments demonstrated that antisense strands of targeted mRNA genes were produced to exonic, but not intronic regions. Finally, small RNAs mapped to both sense and antisense strands of exon-exon junctions, suggesting double-stranded RNA precursors to SINV-induced endo-siRNAs may be synthesized from mature mRNA templates. These results suggest additional complexity in small RNA pathways and gene regulation in the presence of an infecting virus in disease vector mosquitoes. Examination of endo-siRNA production in Aedes aegypti mosquitoes
2012-04-01 | E-GEOD-35161 | biostudies-arrayexpress
Project description:Background: With lower manufacturing cost, high spot density, and flexible probe design, genomic tiling microarrays are ideal for comprehensive transcriptome studies. Typically, transcriptome profiling using microarrays involves reverse transcription, which converts RNA to cDNA. The cDNA is then labeled and hybridized to the probes on the arrays, thus the RNA signals are detected indirectly. Reverse transcription is known to generate artifactual cDNA, in particular the synthesis of second-strand cDNA, leading to false discovery of antisense RNA. To address this issue, we have developed an effective method using RNA that is directly labeled, thus by-passing the cDNA generation. This paper describes the development of this method and its application to mapping transcriptome profiles. Results: RNA extracted from laboratory cultures of Porphyromonas gingivalis was fluorescently labeled with an alkylation reagent and hybridized directly to probes on genomic tiling microarrays specifically designed for this periodontal pathogen. The generated transcriptome profile was strand-specific and produced signals close to background level in most antisense regions of the genome. In contrast, high levels of signal were detected in the antisense regions when the hybridization was done with cDNA. In addition, five antisense areas were tested with independent strand-specific RT-PCR and none to negligible amplification was detected, indicating that the strong antisense cDNA signals were artifacts. Conclusions: An efficient method was developed for mapping transcriptome profiles specific to both coding strands of a bacterial genome. This method chemically labels and uses extracted RNA directly in microarray hybridization. The generated transcriptome profile was free of cDNA artifactual signals. In addition, this method requires fewer processing steps and is more sensitive in detecting small amount of RNA compared to end-labeling methods due to the incorporation of more fluorescent molecules per RNA fragment. This serial of experiments were performed to compare the transcriptome profiles revealed between the use of cDNA (converted from RNA) and RNA. Three samples of cDNA-based method were provided and two samples of RNA-based method were included. The signal intensities of these arrays were normalized based on both the in-between array method and the genomic DNA reference arrays (included) using the R 'tilingarray' package and these experiments were referred in the paper.
2010-12-09 | E-GEOD-25876 | biostudies-arrayexpress
Project description:In flies, repeat-associated small interfering RNAs (rasiRNAs) ensure genomic stability by silencing endogenous selfish genetic elements such as retrotransposons and repetitive sequences. Here, we show that while small interfering RNAs (siRNAs) derive from both the sense and antisense strands of their double-stranded RNA precursors, rasiRNAs arise mainly from the antisense strand. rasiRNA production appear not to require Dicer-1, which makes microRNAs, or Dicer-2, which makes siRNAs, and rasiRNAs lack the 2´,3´ hydroxy termini characteristic of animal siRNA and miRNA. Unlike siRNAs and miRNAs, rasiRNAs function through the Piwi, rather than the Ago, Argonaute protein subfamily. Thus, rasiRNAs define a third RNA silencing pathway distinct from both the miRNA and RNAi pathways. Keywords: gene silencing; post-transcriptional gene regulation; short RNAs; RNAi; rasiRNAs; rasiRNA; microRNAs; microRNA; siRNAs; siRNA
2006-06-30 | GSE4932 | GEO
Project description:The temporal expression of the 23 CfMNPV genes representing all four temporal classes including its 7 unique genes were determined by a modified oligonucleotide-based two-channel DNA microarray. Transcription of the non-coding (antisense) strands of some of the CfMNPV select genes including the polyhedrin gene was also detected by the array analysis. The expression of four host genes varied several fold throughout virus infection. The microarray chip contained oligonucleotide probes for 23 CfMNPV ORFs and their complements. We first developed a novel normalization protocol using Cy5-labeled CfMNPV viral genomic DNA (vgDNA) as equimolar reference standards for each probe in order to overcome the inherent variability problem of the traditional microarray normalization procedures including use of internal standards. Cy3-labeled cDNA was from total RNA isolated at different times post infection of Cf203 insect cells infected with CfMNPV. Host genes were unsuitable for normalization between microarrays. The DNA microarray results were selectively validated by quantitative RT-PCR (qRT-PCR). The nature of the polyhedrin antisense transcription was further investigated using long range RT-PCR analysis. Keywords: Time course, detection of antisense transcripts, viral genomic DNA normalization
2007-05-01 | GSE4783 | GEO
Project description:Purpose: We report the coding and non-coding transcriptomic changes in primary cutaneous squamous cell carcinoma Methods: 4 mm punch biopsies were collected from 7 unmatched healthy and 9 cSCC patients and snap frozen. The library preparation was done using Illumina TruSeq® Stranded Total RNA (with Ribo-Zero Gold) preparation kit. 100 ng of total RNA was depleted of rRNAs using ribo-zero gold magnetic bead based capture-probe system (Illumina Inc.). The remaining RNA was subsequently purified (RNAcleanXP, Beckman Coulter) and fragmented using enzymatic fragmentation. Then first strand synthesis and second strand synthesis were performed and the double stranded cDNA was purified (AMPure XP, Beckman Coulter). The cDNA was end repaired, 3’ adenylated and Illumina sequencing adaptors ligated onto the fragments ends, and the library was purified (AMPure XP). The stranded libraries were amplified with PCR and purified (AMPure XP). The libraries size distribution was validated and quality inspected on a Bioanalyzer. Sequencing was performed on NextSeq 500 instrument using v2 reagent kits according to the manufacturer instructions (Illumina Inc.). Results: On average 49.8 million 100 base pair (bp) paired-end reads were obtained from each sample and genome mapping was on average 55% for all samples. Altered expression of 5,352 protein-coding genes, 908 lncRNAs and 55 circular RNAs was identified. Conclusions: Here, we report the coding and non-coding transcriptomic changes from cSCC samples, along with identification of skin specific transcripts and novel deregulated circRNAs.
2020-03-09 | GSE139505 | GEO
Project description:We examined the biogenesis of mRNA-derived endogenous short-interfering RNAs (endo-siRNAs) in the disease vector mosquito, Aedes aegypti. Under standard conditions, mRNA-derived endo-siRNAs were produced from the bidirectional transcription of tail-tail overlapping gene pairs. Upon infection with the alphavirus, Sindbis virus (SINV), another class of mRNA-derived endo-siRNAs was observed. Genes producing SINV-induced endo-siRNAs were not enriched for overlapping partners or nearby genes, but were enriched for transcripts with long 3'UTRs. Endo-siRNAs from this class derived uniformly from the entire length of the target transcript, and were found to regulate the transcript levels of the genes from which they were derived. Strand-specific qPCR experiments demonstrated that antisense strands of targeted mRNA genes were produced to exonic, but not intronic regions. Finally, small RNAs mapped to both sense and antisense strands of exon-exon junctions, suggesting double-stranded RNA precursors to SINV-induced endo-siRNAs may be synthesized from mature mRNA templates. These results suggest additional complexity in small RNA pathways and gene regulation in the presence of an infecting virus in disease vector mosquitoes.
2012-04-01 | GSE35161 | GEO