Project description:In MINUTE-ChIP, native chromatin is fragmented using Micrococcal nuclease, and subsequently blunted and ligated to double-stranded DNA adaptors that include a T7 RNA polymerase promoter and a sample barcode sequence. Finally, samples are combined and subsequent ChIP reactions are performed with the pooled samples. ChIP material is prepared into an Illumina-compatible library using linear amplification by virtue of T7 RNA polymerase, reverse transcription and a low-cycle library PCR amplification. Native MINUTE-ChIP is based on Mint-ChIP, developed by the Bernstein lab (van Galen et al., 2016; PMID: 26687680). We have introduce unique molecule (UMI) counting and paired-end mapping of the chromatin fragments to this method, which we then termed MINUTE-ChIP for multiplexed indexed unique molecule T7 amplification end-to-end sequencing. Here, we generate a standard curve for H3K27me3 and demonstrate that MINUTE-ChIP has a large linear dynamic range, thus MINUTE-ChIP quantitation is proportional to real quantities.
Project description:We tested the performance of three methods for amplifying single-cell amounts of RNA under ideal conditions: T7-based in vitro transcription; switching mechanism at 5' end of RNA template (SMART) PCR amplification; and global PCR amplification. All methods introduced amplification-dependent noise when mRNA was amplified 108-fold, compared with data from unamplified cDNA. PCR-amplified cDNA demonstrated the smallest number of differences between two parallel replicate samples and the best correlation between independent amplifications from the same cell type, with SMART outperforming global PCR amplification. SMART had the highest true-positive rate and the lowest false-positive rate when comparing expression between two different cell types, but had the lowest absolute discovery rate of all three methods. Direct comparison of the performance of SMART and global PCR amplification on single-cell amounts of total RNA and on single neural stem cells confirmed these findings. Under the conditions tested, PCR amplification was more reliable than linear amplification for detecting true expression differences between samples. SMART amplification had a higher true-positive rate than global amplification, but at the expense of a considerably lower absolute discovery rate and a systematic compression of observed expression ratios. Keywords: Oliginucleotide expression microarrays, T7-based linear amplification; SMART PCR-based amplification; global PCR amplification
Project description:In crosslinked MINUTE-ChIP, formaldehyde-fixed chromatin is fragmented using sonication, blunted and ligated to double-stranded DNA adaptors that include a T7 RNA polymerase promoter and a sample barcode sequence. Finally, samples are combined and subsequent ChIP reactions are performed with the pooled samples. ChIP material is prepared into an Illumina-compatible library using linear amplification by virtue of T7 RNA polymerase, reverse transcription and a low-cycle library PCR amplification. Here, we demonstrate a MINUTE-ChIP for Nanog from formaldehyde-fixed cells using fragmentation by sonication.
Project description:10 normal squamous cervical epitheilia samples, 7 high grade squamous intraepithelial lesions, and 21 invasive squamous cell carcinomas of the cervix samples were obtained using laser capture miicrodissection. Two rounds of T7-based linear RNA amplification using the Arcturus RiboAmp kit were performed for each sample, and assayed using Affymetrix HG_U133A arrays. Keywords: disease state analysis
Project description:This SuperSeries is composed of the following subset Series: GSE3557: Effect of the amount of input total RNA on T7 amplification GSE3558: Effect of in vitro transcription time on the fidelity of T7-based RNA linear amplification GSE3559: Variation in cDNA microarray analysis of gene expression using unamplified poly(A)+ RNA GSE3560: Effects of template switching (TS) primer and cDNA cleanup columns on T7 based RNA linear amplification GSE3561: Effect of ligase on T7 based RNA linear amplification GSE3562: Effect of column cleanup on T7 based RNA linear amplification GSE3563: Correlation between expression levels of different tumors measured by poly(A)+RNA and aRNA Abstract: BACKGROUND: T7 based linear amplification of RNA is used to obtain sufficient antisense RNA for microarray expression profiling. We optimized and systematically evaluated the fidelity and reproducibility of different amplification protocols using total RNA obtained from primary human breast carcinomas and high-density cDNA microarrays. RESULTS: Using an optimized protocol, the average correlation coefficient of gene expression of 11,123 cDNA clones between amplified and unamplified samples is 0.82 (0.85 when a virtual array was created using repeatedly amplified samples to minimize experimental variation). Less than 4% of genes show changes in expression level by 2-fold or greater after amplification compared to unamplified samples. Most changes due to amplification are not systematic both within one tumor sample and between different tumors. Amplification appears to dampen the variation of gene expression for some genes when compared to unamplified poly(A)+ RNA. The reproducibility between repeatedly amplified samples is 0.97 when performed on the same day, but drops to 0.90 when performed weeks apart. The fidelity and reproducibility of amplification is not affected by decreasing the amount of input total RNA in the 0.3-3 micrograms range. Adding template-switching primer, DNA ligase, or column purification of double-stranded cDNA does not improve the fidelity of amplification. The correlation coefficient between amplified and unamplified samples is higher when total RNA is used as template for both experimental and reference RNA amplification. CONCLUSION: T7 based linear amplification reproducibly generates amplified RNA that closely approximates original sample for gene expression profiling using cDNA microarrays. Refer to individual Series
Project description:Abstract: BACKGROUND: T7 based linear amplification of RNA is used to obtain sufficient antisense RNA for microarray expression profiling. We optimized and systematically evaluated the fidelity and reproducibility of different amplification protocols using total RNA obtained from primary human breast carcinomas and high-density cDNA microarrays. RESULTS: Using an optimized protocol, the average correlation coefficient of gene expression of 11,123 cDNA clones between amplified and unamplified samples is 0.82 (0.85 when a virtual array was created using repeatedly amplified samples to minimize experimental variation). Less than 4% of genes show changes in expression level by 2-fold or greater after amplification compared to unamplified samples. Most changes due to amplification are not systematic both within one tumor sample and between different tumors. Amplification appears to dampen the variation of gene expression for some genes when compared to unamplified poly(A)+ RNA. The reproducibility between repeatedly amplified samples is 0.97 when performed on the same day, but drops to 0.90 when performed weeks apart. The fidelity and reproducibility of amplification is not affected by decreasing the amount of input total RNA in the 0.3-3 micrograms range. Adding template-switching primer, DNA ligase, or column purification of double-stranded cDNA does not improve the fidelity of amplification. The correlation coefficient between amplified and unamplified samples is higher when total RNA is used as template for both experimental and reference RNA amplification. CONCLUSION: T7 based linear amplification reproducibly generates amplified RNA that closely approximates original sample for gene expression profiling using cDNA microarrays. This SuperSeries is composed of the SubSeries listed below.
Project description:Zhao et al. Amplification Figure 1 This experiment was designed to evaluate the effect of in vitro transcription time on the fidelity, reproducibility, and yield of T7 based linear amplification. Duplicate reactions were performed at 37 degree for 2, 3, 4, 5, and 6 hours. Two additional 5-hour incubation reactions were stored at 4 degree overnight to determine the effect of low temperature incubation on amplification. BC2 total RNA was amplified using the Jeffrey lab protocol with the G50 column cleanup step. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
Project description:The present microarray studies the differential transcription levels of various genes upon overexpression of tumor suppressor protein SMAR1. The results will lead us to potential targets which are either up/downregulated by SMAR1. Experiment Overall Design: Agilent two-color experiment,Organism: Human ,Slides, Agilent’s Human Microarray G4110B with 22000 features, Labeling kit: Agilents Low input RNA linear amplification Kit Cat # 5184-3523, Labeling Method: T7 promoter based-linear amplification to generate labeled complementary RNA