scholarly journals mRNA detection in budding yeast with single fluorophores

2017 ◽  
Author(s):  
Gable M. Wadsworth ◽  
Rasesh Y. Parikh ◽  
John S. Choy ◽  
Harold D. Kim

Quantitative measurement of mRNA levels in single cells is necessary to understand phenotypic variability within an otherwise isogenic population of cells. Single-molecule mRNA Fluorescence In Situ Hybridization (FISH) has been established as the standard method for this purpose, but current protocols require a long region of mRNA to be targeted by multiple DNA probes. Here, we introduce a new single-probe FISH protocol termed sFISH for budding yeast, Saccharomyces cerevisiae using a single DNA probe labeled with a single fluorophore. In sFISH, we markedly improved probe specificity and signal-to-background ratio by using methanol fixation and inclined laser illumination. We show that sFISH reports mRNA changes that correspond to protein levels and gene copy number. Using this new FISH protocol, we can detect more than 50% of the total target mRNA. We also demonstrate the versatility of sFISH using FRET detection and mRNA isoform profiling as examples. Our FISH protocol with single-fluorophore sensitivity significantly reduces cost and time compared to the conventional FISH protocols and opens up new opportunities to investigate small changes in RNA at the single cell level.

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 6023-6023
Author(s):  
P. Weinberger ◽  
A. Psyrri ◽  
P. Kountourakis ◽  
T. Rampias ◽  
C. Sasaki ◽  
...  

6023 Background: EGFR overexpression correlates with recurrence and with treatment resistance in HNSCC. The mechanisms of EGFR protein overexpression are poorly understood. Nonetheless, previous investigators have not demonstrated a correlation between EGFR gene copy number and protein content, using conventional immunohistochemistry (IHC). The aim of this study was to evaluate the relationship of EGFR gene copy number and protein expression utilizing fluorescence in situ hybridization (FISH) and AQUA, a novel, immunohistochemical method of automated quantitative in situ proteomic analysis which permits subcellular localization. Methods: A tissue microarray composed of 137 HNSCC treated with (chemo)radiation was constructed and analyzed for EGFR copy number by FISH (Vysis/Abbot) and EGFR protein expression (DAKO antibody) using AQUA analysis of EGFR staining scored on a scale of 0–255 and by conventional IHC. Agreement was assessed using kappa. Results: Sixteen (15%) of one-hundred six tumors with FISH results demonstrated EGFR high polysomy and/or gene amplification (FISH+). AQUA demonstrated a range of 3.6–102.2; protein levels assessed by AQUA in the FISH amplified cases were significantly higher (p =0.008) than in the FISH non- amplified ones. Using the EGFR 75th percentile as a cut-off, AQUA and FISH showed significant agreement (percentage of overall agreement 82%, kappa=0.458, p=0.003). To the contrary there was no concordance between FISH and conventional IHC results in this series. Conclusions: The discrepancy between EGFR gene amplification rate and protein expression by IHC reported previously may be due to the limitations and nonquantitative nature of conventional IHC. EGFR protein content correlates with gene copy number if protein content is quantitated and automatically analyzed, as with AQUA. No significant financial relationships to disclose.


2010 ◽  
Vol 28 (13) ◽  
pp. 2174-2180 ◽  
Author(s):  
Rafal Dziadziuszko ◽  
Daniel T. Merrick ◽  
Samir E. Witta ◽  
Adelita D. Mendoza ◽  
Barbara Szostakiewicz ◽  
...  

PurposeThe purpose of this study was to characterize insulin-like growth factor-1 receptor (IGF1R) protein expression, mRNA expression, and gene copy number in surgically resected non–small-cell lung cancers (NSCLC) in relation to epidermal growth factor receptor (EGFR) protein expression, patient characteristics, and prognosis.Patients and MethodsOne hundred eighty-nine patients with NSCLC who underwent curative pulmonary resection were studied (median follow-up, 5.3 years). IGF1R protein expression was evaluated by immunohistochemistry (IHC) with two anti-IGF1R antibodies (n = 179). EGFR protein expression was assessed with PharmDx kit. IGF1R gene expression was evaluated using quantitative reverse transcription polymerase chain reaction (qRT-PCR) from 114 corresponding fresh-frozen samples. IGF1R gene copy number was assessed by fluorescent in situ hybridization using customized probes (n = 181).ResultsIGF1R IHC score was higher in squamous cell carcinomas versus other histologies (P < .001) and associated with stage (P = .03) but not survival (P = .46). IGF1R and EGFR protein expression showed significant correlation (r = 0.30; P < .001). IGF1R gene expression by qRT-PCR was higher in squamous cell versus other histologies (P = .006) and did not associate with other clinical features nor survival (P = .73). Employing criteria previously established for EGFR copy number, patients with IGF1R amplification/high polysomy (n = 48; 27%) had 3-year survival of 58%, patients with low polysomy (n = 87; 48%) had 3-year survival of 47% and patients with trisomy/disomy (n = 46; 25%) had 3-year survival of 35%, respectively (P = .024). Prognostic value of high IGF1R gene copy number was confirmed in multivariate analysis.ConclusionIGF1R protein expression is higher in squamous cell versus other histologies and correlates with EGFR expression. IGF1R protein and gene expression does not associate with survival, whereas high IGF1R gene copy number harbors positive prognostic value.


2011 ◽  
Vol 59 (12) ◽  
pp. 1113-1121 ◽  
Author(s):  
Christina Karlsson ◽  
Mats G. Karlsson

Storage of tissue slides has been claimed to induce dramatically reduced antigen detection particularly for immunohistochemistry (IHC). With tissue microarrays, the necessity to serially cut blocks in order to obtain as much material as possible is obvious. The presumed adverse effect of storage might hamper such an approach. The authors designed an experimental setting consisting of four different storage conditions with storage time of tissue slides of up to 1 year. Detection of proteins, DNA, and mRNA was performed using IHC and in situ hybridization techniques. Slight but significant changes in IHC occurred over time. The most important factor is the primary antibody used: four showed no significant changes, whereas limited decreases in 8 antibodies could be detected by image analysis. Whether the antigen was nuclear or cytoplasmic/membranous did not matter. No major differences between different storage conditions could be shown, but storage at 4C was overall the best procedure. Furthermore, gene copy number aberrations, chromosomal translocations, and the presence of mRNA could be detected on slides stored up to 1 year. In conclusion, in tissues optimally formalin fixed and using modern histological techniques, only minute changes in tissue antigenicity are induced by long-term storage.


2017 ◽  
Vol 21 (3) ◽  
pp. 401-412 ◽  
Author(s):  
Yasutoshi Kuboki ◽  
Christoph A. Schatz ◽  
Karl Koechert ◽  
Sabine Schubert ◽  
Janine Feng ◽  
...  

1985 ◽  
Vol 5 (12) ◽  
pp. 3525-3531
Author(s):  
J K Griffith

Recombinant DNA probes complementary to Chinese hamster metallothionein (MT)-1 and MT-2 mRNAs were used to compare MT gene copy numbers, zinc-induced MT mRNA levels, and uninduced MT mRNA levels in cadmium-resistant (Cdr) Chinese hamster ovary cell lines. Quantitative hybridization analyses determined that the MT-1 and MT-2 genes are each present at approximately single-copy levels in the genome of cell line Cdr2C10 and are coordinately amplified approximately 7, 3, and 12 times over the Cdr2C10 value in the genomes of cell lines Cdr20F4, Cdr30F9, and Cdr200T1, respectively. The maximum zinc-induced MT-1 mRNA concentrations in cell lines Cdr20F4, Cdr30F9, and Cdr200T1 were equal to 1, 3, and 15 times that measured in Cdr2C10, respectively. Similarly, the maximum zinc-induced MT-2 mRNA concentrations were equal to 1, 3, and 14 times that measured in Cdr2C10, respectively, and in each instance they were 90 to 150 times greater than their respective concentrations in uninduced cells. Thus, relative MT gene numbers are closely correlated with both zinc-induced and uninduced MT mRNA levels in Cdr2C10, Cdr30F9, and Cdr200T1, but not in Cdr20F4. Each of the latter two lines possesses structurally altered chromosomes whose breakpoints are near the MT locus. Nonetheless, the ratio of the levels of MT-1 to MT-2 mRNAs was constant in each of the four cell lines, including Cdr20F4. These results demonstrate that MT-1 and MT-2 mRNAs are induced coordinately in each Cdr cell line. Therefore, the coordination of the induction of MT-1 and MT-2 mRNA is independent of MT gene amplification, MT gene rearrangement, and the relative inducibilities of amplified MT genes. However, MT mRNA and protein levels each indicate that MT-1 and MT-2 expression is non-coordinate in uninduced cells. Thus, regulation of MT expression may involve two different mechanisms which are differentially operative in induced and uninduced cells.


2018 ◽  
Vol 26 (3) ◽  
pp. 434-439 ◽  
Author(s):  
Catherine P. James ◽  
Mona Bajaj-Elliott ◽  
Razan Abujaber ◽  
Frida Forya ◽  
Nigel Klein ◽  
...  

2019 ◽  
Vol 20 (3) ◽  
pp. 693 ◽  
Author(s):  
Vanessa Lattimore ◽  
John Pearson ◽  
Arthur Morley-Bunker ◽  
kConFab Investigators ◽  
Amanda Spurdle ◽  
...  

BRCA1 and BRCA2 spliceogenic variants are often associated with an elevated risk of breast and ovarian cancers. Analyses of BRCA1 and BRCA2 splicing patterns have traditionally used technologies that sample a population of cells but do not account for the variation that may be present between individual cells. This novel proof of concept study utilises RNA in situ hybridisation to measure the absolute expression of BRCA1 and BRCA2 mRNA splicing events in single lymphoblastoid cells containing known spliceogenic variants (BRCA1c.671-2 A>G or BRCA2c.7988 A>T). We observed a large proportion of cells (>42%) in each sample that did not express mRNA for the targeted gene. Increased levels (average mRNA molecules per cell) of BRCA2 ∆17_18 were observed in the cells containing the known spliceogenic variant BRCA2c.7988 A>T, but cells containing BRCA1c.671-2 A>G were not found to express significantly increased levels of BRCA1 ∆11, as had been shown previously. Instead, we show for each variant carrier sample that a higher proportion of cells expressed the targeted splicing event compared to control cells. These results indicate that BRCA1/2 mRNA is expressed stochastically, suggesting that previously reported results using RT-PCR may have been influenced by the number of cells with BRCA1/2 mRNA expression and may not represent an elevation of constitutive mRNA expression. Detection of mRNA expression in single cells allows for a more comprehensive understanding of how spliceogenic variants influence the expression of mRNA isoforms. However, further research is required to assess the utility of this technology to measure the expression of predicted spliceogenic BRCA1 and BRCA2 variants in a diagnostic setting.


2014 ◽  
Vol 307 (8) ◽  
pp. L632-L642 ◽  
Author(s):  
Richard Seonghun Nho ◽  
Jintaek Im ◽  
Yen-Yi Ho ◽  
Polla Hergert

Idiopathic pulmonary fibrosis (IPF) is a lethal and progressive lung disease characterized by persistent (myo)fibroblasts and the relentless accumulation of collagen matrix. Unlike normal lung fibroblasts, IPF lung fibroblasts have suppressed forkhead box O3a (FoxO3a) activity, which allows them to expand in this diseased environment. microRNA-96 (miR-96) has recently been found to directly bind to the 3′-untranslated region of FoxO3a mRNA, which subsequently inhibits its function. We examined whether aberrantly low FoxO3a expression is in part due to increased miR-96 levels in IPF fibroblasts on polymerized collagen, thereby causing IPF fibroblasts to maintain their pathological properties. miR-96 expression was upregulated in IPF fibroblasts compared with control fibroblasts when cultured on collagen. In contrast, FoxO3a mRNA levels were reduced in most IPF fibroblasts. However, when miR-96 function was inhibited, FoxO3a mRNA and protein expression were increased, suppressing IPF fibroblast proliferation and promoting their cell death in a dose-dependent fashion. Likewise, FoxO3a and its target proteins p21, p27, and Bim expression was also increased in the presence of a miR-96 inhibitor in IPF fibroblasts. However, when control fibroblasts were treated with miR-96 mimic, FoxO3a, p27, p21, and Bim mRNA and protein levels were decreased. In situ hybridization analysis further revealed the presence of enhanced miR-96 expression in cells within the fibroblastic foci of IPF lung tissue. Our results suggest that when IPF fibroblasts interact with collagen-rich matrix, pathologically altered miR-96 expression inhibits FoxO3a function, causing IPF fibroblasts to maintain their pathological phenotype, which may contribute to the progression of IPF.


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