Project description:To accurately evaluate expression levels of target genes, stable internal reference genes is required for normalization of quantitative real-time PCR (qRT-PCR) data. However, there have been no systematical investigation on the stability of reference genes used in the bedstraw weed, Galium aparine L. (BGA). In this study, the expression profiles of seven traditionally used reference genes, namely 18S, 28S, ACT, GAPDH, EF1α, RPL7 and TBP in BGA were assessed under both biotic (developmental time and tissue), and abiotic (temperature, regions and herbicide) conditions. Four analytical algorithms (geNorm, Normfinder, BestKeeper and the ΔCt method) were used to analyze the suitability of these genes as internal reference genes. RefFinder, a comprehensive analytical software, was used to rank the overall stability of the candidate genes. The optimal normalization internal control genes were ranked as: 28S and RPL7 were best for all the different experimental conditions (developmental stages, tissues, temperature, regions and herbicide treatment); 28S and RPL7 for developmental stages; TBP and GAPDH for different tissues; 28S and GAPDH were relatively stable for different temperature; 28S and TBP were suitable for herbicide treatment. A specific set of reference genes were recommended for each experimental condition in BGA.
Project description:BackgroundWith the current rise in obesity-related morbidities, real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) has become a widely used method for assessment of genes expressed and regulated by adipocytes. In order to measure accurate changes in relative gene expression and monitor intersample variability, normalization to endogenous control genes that do not change in relative expression is commonly used with qRT-PCR determinations. However, historical evidence has clearly demonstrated that the expression profiles of traditional control genes (e.g., β-actin, GAPDH, α-tubulin) are differentially regulated across multiple tissue types and experimental conditions.Methodology/principal findingsTherefore, we validated six commonly used endogenous control genes under diverse experimental conditions of inflammatory stress, oxidative stress, synchronous cell cycle progression and cellular differentiation in 3T3-L1 adipocytes using TaqMan qRT-PCR. Under each study condition, we further evaluated the impact of reference gene selection on experimental outcome using examples of target genes relevant to adipocyte function and differentiation. We demonstrate that multiple reference genes are regulated in a condition-specific manner that is not suitable for use in target gene normalization.Conclusion/significanceData are presented demonstrating that inappropriate reference gene selection can have profound influence on study conclusions ranging from divergent statistical outcome to inaccurate data interpretation of significant magnitude. This study validated the use of endogenous controls in 3T3-L1 adipocytes and highlights the impact of inappropriate reference gene selection on data interpretation and study conclusions.
Project description:UnlabelledZi geese (Anser anser domestica) belong to the white geese and are excellent layers with a superior feed-to-egg conversion ratio. Quantitative gene expression analysis, such as Real-time qRT-PCR, will provide a good understanding of ovarian function during egg-laying and consequently improve egg production. However, we still don't know what reference genes in geese, which show stable expression, should be used for such quantitative analysis. In order to reveal such reference genes, the stability of seven genes were tested in five tissues of Zi geese.Methodology/principal findingsThe relative transcription levels of genes encoding hypoxanthine guanine phosphoribosyl transferase 1 (HPRT1), β-actin (ACTB), β-tubulin (TUB), glyceraldehyde-3-phosphate-dehydrogenase (GADPH), succinate dehydrogenase flavoprotein (SDH), 28S rRNA (28S) and 18S rRNA (18S) have been quantified in heart, liver, kidney, muscle and ovary in Zi geese respectively at different developmental stages (1 d, 2, 4, 6 and 8 months). The expression stability of these genes was analyzed using geNorm, NormFinder and BestKeeper software.ConclusionsThe expression of 28S in heart, GAPDH in liver and ovary, ACTB in kidney and HPRT1 in muscle are the most stable genes as identified by the three different analysis methods. Thus, these genes are recommended for use as candidate reference genes to compare mRNA transcription in various developmental stages of geese.
Project description:The use of reverse transcription quantitative PCR technology to assess gene expression levels requires an accurate normalization of data in order to avoid misinterpretation of experimental results and erroneous analyses. Despite being the focus of several transcriptomics projects, oaks, and particularly cork oak (Quercus suber), have not been investigated regarding the identification of reference genes suitable for the normalization of real-time quantitative PCR data. In this study, ten candidate reference genes (Act, CACs, EF-1α, GAPDH, His3, PsaH, Sand, PP2A, ß-Tub and Ubq) were evaluated to determine the most stable internal reference for quantitative PCR normalization in cork oak. The transcript abundance of these genes was analysed in several tissues of cork oak, including leaves, reproduction cork, and periderm from branches at different developmental stages (1-, 2-, and 3-year old) or collected in different dates (active growth period versus dormancy). The three statistical methods (geNorm, NormFinder, and CV method) used in the evaluation of the most suitable combination of reference genes identified Act and CACs as the most stable candidates when all the samples were analysed together, while ß-Tub and PsaH showed the lowest expression stability. However, when different tissues, developmental stages, and collection dates were analysed separately, the reference genes exhibited some variation in their expression levels. In this study, and for the first time, we have identified and validated reference genes in cork oak that can be used for quantification of target gene expression in different tissues and experimental conditions and will be useful as a starting point for gene expression studies in other oaks.
Project description:Despite its superiority for evaluating gene expression, real-time quantitative polymerase chain reaction (qPCR) results can be significantly biased by the use of inappropriate reference genes under different experimental conditions. Reaumuria soongorica is a dominant species of desert ecosystems in arid central Asia. Given the increasing interest in ecological engineering and potential genetic resources for arid agronomy, it is important to analyze gene function. However, systematic evaluation of stable reference genes should be performed prior to such analyses. In this study, the stabilities of 10 candidate reference genes were analyzed under 4 kinds of abiotic stresses (drought, salt, dark, and heat) within 4 accessions (HG010, HG020, XGG030, and XGG040) from 2 different habitats using 3 algorithms (geNorm, NormFinder, and BestKeeper). After validation of the ribulose-1,5-bisphosphate carboxylase/oxygenase large unite (rbcL) expression pattern, our data suggested that histone H2A (H2A) and eukaryotic initiation factor 4A-2 (EIF4A2) were the most stable reference genes, cyclophilin (CYCL) was moderate, and elongation factor 1α (EF1α) was the worst choice. This first systematic analysis for stably expressed genes will facilitate future functional analyses and deep mining of genetic resources in R. soongorica and other species of the Reaumuria genus.
Project description:Dendroctonus valens is the main pest of the genus Pinus. To facilitate gene expression analyses, suitable reference genes for adults and mature larvae of D. valens under different temperature conditions were determined. In particular, we obtained the sequences of candidate reference genes, ACT, TUB, SHDA, PRS18, 18S rRNA, and CYP4G55, from transcriptome data. Real-time quantitative PCR was used to analyze gene expression, and geNorm, NormFinder, and BestKeeper were used to evaluate expression stability. Under different temperature conditions, the expression levels of 18S rRNA, PRS18, and TUB were stable in adults, in which 18S rRNA > PRS18 > TUB. In mature larvae, the expression levels of TUB, 18S rRNA, and SDHA were stable, in which TUB > 18S rRNA > SDHA. The combination of 18S rRNA and PRS18 is recommended for studies of gene expression in adults and the combination of 18S rRNA and TUB is effective for studies of gene expression in mature larvae of D. valens under different temperature conditions.
Project description:BackgroundQuantitative real-time PCR (qPCR) is a widely used technique for gene expression analysis. Its reliability is highly dependent upon selection of the appropriate reference genes for accurate gene expression normalization. In this study, we investigated the expression stability of 10 commonly used reference genes in a mouse myocardial infarction model.Methods & resultsThe expression stability of the 10 reference genes (Actb, B2m, Eef1a1, Gapdh, Hprt, Polr2a, Ppia, Rpl13a, Tbp, Tpt1) was analyzed using the geNorm software. Overall, the combination of Hprt, Rpl13a and Tpt1 was the most stable reference gene set in our experiments. Gapdh, Polr2a and Actb consistently showed the highest gene expression variability and the expression levels of Gapdh, Polr2a, Actb, B2m and Eef1a1 were found to be selectively up- or downregulated after myocardial infarction. We normalized the expression of Nppb and Vcam1, using different reference gene strategies and demonstrated that their induction after myocardial infarction was most clearly revealed with the optimal reference gene combination. However, the use of suboptimal reference gene combinations resulted in detrimental effects on gene expression levels and variability with a gradual loss of the expression differences and a significant reduction in statistical power.ConclusionsHprt, Rpl13a and Tpt1 are a set of stably expressed reference genes for accurate gene expression normalization in myocardial infarction studies in mice. We found that Gapdh, Polr2a and Actb display high expression variability in mouse myocardial infarction tissues and that loss of statistical power and increase in sample size are the evident consequences of choosing suboptimal combinations of reference genes. We furthermore caution against the use of Gapdh, Polr2a, Actb, B2m and Eef1a1 for gene expression normalization in myocardial infarction studies because of selective up- or downregulation after myocardial infarction, which could potentially lead to biased study outcomes.
Project description:BackgroundReference genes, which are often referred to housekeeping genes, are frequently used to normalize mRNA levels between different samples. However the expression level of these genes may vary among tissues or cells, and may change under certain circumstances. Thus the selection of reference gene(s) is critical for gene expression studies. For this purpose, 10 commonly used housekeeping genes were investigated in isolated human neutrophils.ResultsInitial screening of the expression pattern demonstrated that 3 of the 10 genes were expressed at very low levels in neutrophils and were excluded from further analysis. The range of expression stability of the other 7 genes was (from most stable to least stable): GNB2L1 (Guanine nucleotide binding protein, beta polypeptide 2-like 1), HPRT1 (Hypoxanthine phosphoribosyl transferase 1), RPL32 (ribosomal protein L32), ACTB (beta-actin), B2M (beta-2-microglobulin), GAPD (glyceraldehyde-3-phosphate dehydrogenase) and TBP (TATA-binding protein). Relative expression levels of the genes (from high to low) were: B2M, ACTB, GAPD, RPL32, GNB2L1, TBP, and HPRT1.ConclusionOur data suggest that GNB2L1, HPRT1, RPL32, ACTB, and B2M may be suitable reference genes in gene expression studies of neutrophils.
Project description:BackgroundRT-qPCR is a preferred method for rapid and reliable quantification of gene expression studies. Appropriate application of RT-qPCR in such studies requires the use of reference gene(s) as an internal control to normalize mRNA levels between different samples for an exact comparison of gene expression level. However, recent studies have shown that no single reference gene is universal for all experiments. Thus, the identification of high quality reference gene(s) is of paramount importance for the interpretation of data generated by RT-qPCR. Only a few studies on reference genes have been done in plants and none in peach (Prunus persica L. Batsch). Therefore, the present study was conducted to identify suitable reference gene(s) for normalization of gene expression in peach.ResultsIn this work, eleven reference genes were investigated in different peach samples using RT-qPCR with SYBR green. These genes are: actin 2/7 (ACT), cyclophilin (CYP2), RNA polymerase II (RP II), phospholipase A2 (PLA2), ribosomal protein L13 (RPL13), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), 18S ribosomal RNA (18S rRNA), tubblin beta (TUB), tubblin alpha (TUA), translation elongation factor 2 (TEF2) and ubiquitin 10 (UBQ10). All eleven reference genes displayed a wide range of Cq values in all samples, indicating that they expressed variably. The stability of these genes except for RPL13 was determined by three different descriptive statistics, geNorm, NormFinder and BestKeeper, which produced highly comparable results.ConclusionOur study demonstrates that expression stability varied greatly between genes studied in peach. Based on the results from geNorm, NormFinder and BestKeeper analyses, for all the sample pools analyzed, TEF2, UBQ10 and RP II were found to be the most suitable reference genes with a very high statistical reliability, and TEF2 and RP II for the other sample series, while 18S rRNA, RPL13 and PLA2 were unsuitable as internal controls. GAPDH and ACT also performed poorly and were less stable in our analysis. To achieve accurate comparison of levels of gene expression, two or more reference genes must be used for data normalization. The combinations of TEF2/UBQ10/RP II and TEF2/RP II were suggested for use in all samples and subsets, respectively.
Project description:BackgroundAccurate evaluation of gene expression requires normalization relative to the expression of reliable reference genes. Expression levels of "classical" reference genes can differ, however, across experimental conditions. Although quantitative real-time PCR (qRT-PCR) has been used extensively to decipher gene function in the sweetpotato whitefly Bemisia tabaci, a world-wide pest in many agricultural systems, the stability of its reference genes has rarely been validated.ResultsIn this study, 15 candidate reference genes from B. tabaci were evaluated using two Excel-based algorithms geNorm and Normfinder under a diverse set of biotic and abiotic conditions. At least two reference genes were selected to normalize gene expressions in B. tabaci under experimental conditions. Specifically, for biotic conditions including host plant, acquisition of a plant virus, developmental stage, tissue (body region of the adult), and whitefly biotype, ribosomal protein L29 was the most stable reference gene. In contrast, the expression of elongation factor 1 alpha, peptidylprolyl isomerase A, NADH dehydrogenase, succinate dehydrogenase complex subunit A and heat shock protein 40 were consistently stable across various abiotic conditions including photoperiod, temperature, and insecticide susceptibility.ConclusionOur finding is the first step toward establishing a standardized quantitative real-time PCR procedure following the MIQE (Minimum Information for publication of Quantitative real time PCR Experiments) guideline in an agriculturally important insect pest, and provides a solid foundation for future RNA interference based functional study in B. tabaci.