scholarly journals Standardization of Gene Expression Quantification by Absolute Real-Time qRT-PCR System Using a Single Standard for Marker and Reference Genes

2010 ◽  
Vol 5 ◽  
pp. BMI.S5596 ◽  
Author(s):  
Yi-Hong Zhou ◽  
Vinay R. Raj ◽  
Eric Siegel ◽  
Liping Yu
Keyword(s):  
Gene Expression ◽  
Real Time ◽  
Gene Expression Data ◽  
Reference Genes ◽  
Pcr Analysis ◽  
Expression Data ◽  
Internal Reference ◽  
Expression Ratio ◽  
Qrt Pcr ◽  
Single Standard

In the last decade, genome-wide gene expression data has been collected from a large number of cancer specimens. In many studies utilizing either microarray-based or knowledge-based gene expression profiling, both the validation of candidate genes and the identification and inclusion of biomarkers in prognosis-modeling has employed real-time quantitative PCR on reverse transcribed mRNA (qRT-PCR) because of its inherent sensitivity and quantitative nature. In qRT-PCR data analysis, an internal reference gene is used to normalize the variation in input sample quantity. The relative quantification method used in current real-time qRT-PCR analysis fails to ensure data comparability pivotal in identification of prognostic biomarkers. By employing an absolute qRT-PCR system that uses a single standard for marker and reference genes (SSMR) to achieve absolute quantification, we showed that the normalized gene expression data is comparable and independent of variations in the quantities of sample as well as the standard used for generating standard curves. We compared two sets of normalized gene expression data with same histological diagnosis of brain tumor from two labs using relative and absolute real-time qRT-PCR. Base-10 logarithms of the gene expression ratio relative to ACTB were evaluated for statistical equivalence between tumors processed by two different labs. The results showed an approximate comparability for normalized gene expression quantified using a SSMR-based qRT-PCR. Incomparable results were seen for the gene expression data using relative real-time qRT-PCR, due to inequality in molar concentration of two standards for marker and reference genes. Overall results show that SSMR-based real-time qRT-PCR ensures comparability of gene expression data much needed in establishment of prognostic/predictive models for cancer patients–-a process that requires large sample sizes by combining independent sets of data.

scholarly journals Selection and Validation of Appropriate Reference Genes for Real-Time Quantitative PCR Analysis in Needles of Larix olgensis under Abiotic Stresses

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 193
Author(s):  
Dandan Li ◽  
Sen Yu ◽  
Minzhen Zeng ◽  
Xiao Liu ◽  
Jia Yang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heat Stress ◽  
Real Time ◽  
Reference Genes ◽  
Pcr Analysis ◽  
Stable Gene ◽  
Larix Olgensis ◽  
Qrt Pcr ◽  
Study Gene Expression ◽  
Selection Of

Larix olgensis Henry is an important afforestation species in northeastern China because of its fast juvenile growth, high-quality timber, and significant economic and ecological values. The selection of appropriate reference genes is necessary for the normalization of gene expression determination during quantitative real-time polymerase chain reaction (qRT-PCR) experiments. In this study, qRT-PCR was used to study gene expression. Three software packages geNorm, NormFinder, BestKeeper were used, and a comprehensive ranking of candidate reference genes was produced based on their output to evaluate the expression stability of 16 candidate reference genes from L. olgensis under drought, salt, cold, and heat stress. PP2A-1 and GAPDH ranked as the most stable reference genes under drought and cold stress, PP2A-1 and UBQ10 were most stable under salt stress, and TIP41 and ACT2 were most stable under heat stress. The least stable gene was ADP, which ranked the last under all treatments. Expression profile analysis of the antioxidant gene CAT using the two most stable and the single least stable reference genes under each stress further verified that the selected reference genes were suitable for gene expression normalization. This study provides an important foundation for the selection of suitable reference genes for the normalization and quantification of L. olgensis gene expression under abiotic stress conditions.

Selection of Reference Genes for Transcription Studies on Adventitious Root Induction in Olive (Olea Europaea L.) Microshoots Considering Co-expression and Average Transcriptional Stability

2020 ◽  
Author(s):  
Carlos Noceda ◽  
Augusto Peixe ◽  
Birgit Arnholdt-Schmitt
Keyword(s):  
Gene Expression ◽  
Gene Expression Data ◽  
Reference Genes ◽  
Ad Hoc ◽  
Root Induction ◽  
Expression Data ◽  
Internal Reference ◽  
Experimental Conditions ◽  
Selection Of

Abstract BackgroungSelection of reference genes (RGs) for normalization of PCR-gene expression data includes two crucial steps: determination of the among-sample transcriptionally more stable genes and subsequent choosing of the most suitable genes as internal controls. Both steps can be carried-out through generally accepted strategies each having different strengths and weaknesses. The present study proposes to reinforce normalization of gene expression data by integrating and adding analytical revision at critical steps of those accepted procedures. Especially crucial is to counterbalance a higher representative number of RGs with a correspondent increase in their average transcriptional instability or a generalised co-expression trend among the samples. This methodological study used in vitro olive adventitious rooting as an experimental system, since the underlying morphogenetic process -wich is common to diverse species- is still not completely understood.ResultsFirstly, RG candidates were ranked according to transcriptional stability following a simple statistical method that reduces biasing effects of concomitant, systematic biological variations associated to experimental conditions, such as the variations caused by gene co-regulation. Those types of systematic co-variation are unconsidered by several popular ad hoc informatics programmes. To select the adequate genes among those already ranked, an algorithm of one of the ad hoc informatics programmes (GeNorm) was adapted to allow partial automatization of RG selection for any strategy of transcriptional-gene stability ordering. In order to delve into the resulting possible RG sets suitability for inter-assay comparisons and technical-error compensation, separate statistics were formulated. The achieved results were compared with those obtained by standard stability ranking methods. Finally, a double evaluation was performed to accurately contrast two choice RG sets. The whole strategy was applied to a panel considering several independent factors, but the suitability of the obtained putative RG sets was tested for cases restricted to fewer variables. H2B, OUB and ACT are valid for normalization in transcriptional studies on olive microshoot rooting when comparing treatments, time points and assays.ConclusionsThe set of genes identified as internal reference is now available for wider expression studies on any target gene in similar biological systems. The overall methodology aims to constitute a guide for general application.

scholarly journals Selection of Reliable Reference Genes for Real-time qRT-PCR Analysis of Zi Geese (<italic>Anser anser domestica</italic>) Gene Expression

2013 ◽  
Vol 26 (3) ◽  
pp. 423-432 ◽  
Author(s):  
Hong Ji ◽  
Jianfa Wang ◽  
Juxiong Liu ◽  
Jingru Guo ◽  
Zhongwei Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Real Time ◽  
Reference Genes ◽  
Pcr Analysis ◽  
Anser Anser ◽  
Qrt Pcr ◽  
Selection Of

Stability of reference genes for normalization of reverse transcription quantitative real-time PCR (RT-qPCR) data in bovine blastocysts produced by IVF, ICSI and SCNT

Zygote ◽  
2013 ◽  
Vol 22 (4) ◽  
pp. 505-512 ◽  
Author(s):  
Charlotte Luchsinger ◽  
María Elena Arias ◽  
Tamara Vargas ◽  
Marcos Paredes ◽  
Raúl Sánchez ◽  
...  
Keyword(s):  
Gene Expression ◽  
Real Time ◽  
Gene Expression Data ◽  
Internal Control ◽  
Reverse Transcription ◽  
Reference Genes ◽  
Quantitative Estimation ◽  
Expression Patterns ◽  
Preimplantation Embryos ◽  
Expression Data

SummaryReverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is a sensitive and accurate tool for quantitative estimation of gene transcription levels in preimplantation embryos. To control for possible experimental variations, gene expression data must be normalized using internal control genes commonly known as reference genes. However, the stability of reference genes can vary depending on the state of development and/or experimental conditions; hence the assessment of their stability is essential before initiating a gene expression analysis. In the present study, we used RT-qPCR to measure the transcript levels of 10 commonly used reference genes and analyzed their expression stability in bovine blastocysts produced by in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and somatic cell nuclear transfer (SCNT). Using the geNorm program, we found the best combination of genes to normalize gene expression data in bovine embryos at the blastocyst stage produced by IVF (HMBS, SF3A1, and HPRT1), ICSI (H2A, HMBS, and GAPDH), SCNT (ACTB, SF3A1, and SDHA) and/or between blastocysts produced by these methods (GAPDH, HMBS and EEF1A2). We also demonstrated that not only the culture conditions may affect the expression patterns in bovine blastocysts but also the choice of embryo production method may have an important effect.

Identification of stable reference genes in differentiating human pluripotent stem cells

2015 ◽  
Vol 47 (6) ◽  
pp. 232-239 ◽  
Author(s):  
Gustav Holmgren ◽  
Nidal Ghosheh ◽  
Xianmin Zeng ◽  
Yalda Bogestål ◽  
Peter Sartipy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Gene Expression Data ◽  
Pluripotent Stem Cells ◽  
Reference Genes ◽  
Cell Types ◽  
Human Pluripotent Stem Cells ◽  
Expression Data ◽  
Large Variability ◽  
The Stability

Reference genes, often referred to as housekeeping genes (HKGs), are frequently used to normalize gene expression data based on the assumption that they are expressed at a constant level in the cells. However, several studies have shown that there may be a large variability in the gene expression levels of HKGs in various cell types. In a previous study, employing human embryonic stem cells (hESCs) subjected to spontaneous differentiation, we observed that the expression of commonly used HKG varied to a degree that rendered them inappropriate to use as reference genes under those experimental settings. Here we present a substantially extended study of the HKG signature in human pluripotent stem cells (hPSC), including nine global gene expression datasets from both hESC and human induced pluripotent stem cells, obtained during directed differentiation toward endoderm-, mesoderm-, and ectoderm derivatives. Sets of stably expressed genes were compiled, and a handful of genes (e.g., EID2, ZNF324B, CAPN10, and RABEP2) were identified as generally applicable reference genes in hPSCs across all cell lines and experimental conditions. The stability in gene expression profiles was confirmed by reverse transcription quantitative PCR analysis. Taken together, the current results suggest that differentiating hPSCs have a distinct HKG signature, which in some aspects is different from somatic cell types, and underscore the necessity to validate the stability of reference genes under the actual experimental setup used. In addition, the novel putative HKGs identified in this study can preferentially be used for normalization of gene expression data obtained from differentiating hPSCs.

scholarly journals Comparison of Reliable Reference Genes Following Different Hormone Treatments by Various Algorithms for qRT-PCR Analysis of Metasequoia

2018 ◽  
Vol 20 (1) ◽  
pp. 34 ◽  
Author(s):  
Jing-Jing Wang ◽  
Shuo Han ◽  
Weilun Yin ◽  
Xinli Xia ◽  
Chao Liu
Keyword(s):  
Gene Expression ◽  
Reference Genes ◽  
Elongation Factor ◽  
Pcr Analysis ◽  
Qrt Pcr ◽  
Gene Normalization ◽  
Accurate Normalization ◽  
Suitable Reference ◽  
Different Tissues ◽  
Gene Expression Levels

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is the most sensitive technique for evaluating gene expression levels. Choosing appropriate reference genes for normalizing target gene expression is important for verifying expression changes. Metasequoia is a high-quality and economically important wood species. However, few systematic studies have examined reference genes in Metasequoia. Here, the expression stability of 14 candidate reference genes in different tissues and following different hormone treatments were analyzed using six algorithms. Candidate reference genes were used to normalize the expression pattern of FLOWERING LOCUS T and pyrabactin resistance-like 8. Analysis using the GrayNorm algorithm showed that ACT2 (Actin 2), HIS (histone superfamily protein H3) and TATA (TATA binding protein) were stably expressed in different tissues. ACT2, EF1α (elongation factor-1 alpha) and HIS were optimal for leaves treated with the flowering induction hormone solution, while Cpn60β (60-kDa chaperonin β-subunit), GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and HIS were the best reference genes for treated buds. EF1α, HIS and TATA were useful reference genes for accurate normalization in abscisic acid-response signaling. Our results emphasize the importance of validating reference genes for qRT-PCR analysis in Metasequoia. To avoid errors, suitable reference genes should be used for different tissues and hormone treatments to increase normalization accuracy. Our study provides a foundation for reference gene normalization when analyzing gene expression in Metasequoia.

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