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- Wu, Chenglin, et al.
(författare)
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Profiling and genotyping individual mRNA molecules through in situ sequencing of super rolling circle amplification products
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We have recently developed a technology for localized sequence library preparation with rolling-circle amplification (RCA) as an approach for in situ sequencing. This method involves generation of clonally amplified and specially confined substrates for next-generation sequencing within the preserved context of cells and tissues. Our approach combines padlock probing, RCA, and sequencing-by-ligation chemistry that can resolve expression profiles of sets of genes and mutations in tissues without loss of histological context. Like other fluorescence-based assays, it can be hindered by high level of background fluorescence. To achieve high signal-to-noise ratios, we now describe a method to boost the amplification generated by RCA of padlock probes in situ by super RCA (sRCA). In this technique, a second padlock probe is hybridized, ligated and amplified on the first RCA product for enhanced, localized amplification. We describe and compare different sRCA strategies where gap-fill ligation was showed to be most efficient. The sRCA products co-localize and have comparable sizes as RCA products but they display at least two fold higher signal intensity. This increase in signal to noise also proved to result in two folds increase in the number of sRCA products detected. By combining sRCA with in situ sequencing for highly multiplex detection in tissue a four-time increase was seen. In summary, we demonstrate that sRCA can significantly increase the performance of padlock-based in situ sequencing for gene expression profiling of tissue sections, enabling detection of low abundant transcripts and the analysis of also highly auto-fluorescent samples.
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| 2. |
- Wu, Chenglin, et al.
(författare)
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RollFISH achieves robust quantification of single-molecule RNA biomarkers in paraffin-embedded tumor tissue samples
- 2018
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Ingår i: Communications biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 1
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Tidskriftsartikel (refereegranskat)abstract
- Single-molecule RNA fluorescence in situ hybridization (smFISH) represents a promising approach to quantify the expression of clinically useful biomarkers in tumor samples. However, routine application of smFISH to formalin-fixed, paraffin-embedded (FFPE) samples is challenging due to the low signal intensity and high background noise. Here we present RollFISH, a method combining the specificity of smFISH with the signal boosting of rolling circle amplification. We apply RollFISH to quantify widely used breast cancer biomarkers in cell lines and FFPE samples. Thanks to the high signal-to-noise ratio, we can visualize selected biomarkers at low magnification (20 x) across entire tissue sections, and thus assess their spatial heterogeneity. Lastly, we apply RollFISH to quantify HER2 mRNA in 150 samples on a single tissue microarray, achieving a sensitivity and specificity of detection of HER2-positive samples of similar to 90%. RollFISH is a robust method for quantifying the expression and intratumor heterogeneity of biomarkers in FFPE tissues.
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