Reference Gene Validation for Quantitative Real-time PCR Studies in Amphibian Kidney-derived A6 Epithelial Cells

Quantitative real-time polymerase chain reaction is a widely used technique that relies on reference genes for the normalisation of gene expression. These reference genes are constitutively expressed and must remain stable across all samples and treatments. Stability of housekeeping genes may vary and must be optimised for a specific tissue, sample or cell line. Here we present a study screening for possible reference gene candidates, eef1a1, rpl8, sub1.L, clta, H4 and odc1, in the Xenopus laevis (A6) kidney cell line. Quantification cycle results were analysed using geNorm to calculate the average expression stability and the coefficient of variation (CV) for each candidate reference gene. All of the tested genes met the guidelines for stable reference genes, namely an average expression stability of < 0.5 and a CV value of < 0.2, with eef1a1 > sub1.L > rpl8 > clta > odc1 > H4. By using pairwise variation analysis, the optimal number of reference targets was determined to be 2. As such, we report that the reference genes eef1a1 and sub1.L should be used to achieve optimal normalisation in A6 cells.

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Selection of reference genes for quantitative real-time PCR evaluation of chronic erythropoietin treatment effect on the SH-SY5Y and PC12 cells

Open Chemistry ◽

10.2478/s11532-012-0164-5 ◽

2013 ◽

Vol 11 (3) ◽

pp. 348-357

Author(s):

Klemen Španinger ◽

Arthur Sytkowski ◽

Nataša Debeljak

Keyword(s):

Real Time ◽

Pc12 Cells ◽

Reference Gene ◽

Reference Genes ◽

Housekeeping Genes ◽

Expression Stability ◽

Normalization Gene ◽

Erythropoietin Treatment ◽

Control Plate ◽

Selection Of

AbstractAbstract The quantitative real-time polymerase chain reaction (qPCR) is a sensitive technique for examining the influence of erythropoietin (Epo) on gene expression. A critical and fundamental step for data analysis is the selection of and normalization to the optimal reference gene(s). We identified appropriate reference gene(s) among 32 genes during chronic recombinant human Epo (rHuEpo) treatment of SH-SY5Y cells using TaqMan human Express Endogenous Control Plate. Expression stability of the selected reference gene (RPLP) was retested with qPCR, together with two commonly used reference genes (GAPDH, ACTB) and six genes of interest (EPOR, EPO, STAT5B, STAT5A, JUN, AKT). In PC12 cells, three commonly used reference genes (Gapdh, CycA and Ywhaz) and seven genes of interest (EpoR, Epo, Stat5b, Stat5a, Jun, Akt, Fos) were evaluated. For the evaluation of expression stability, geNorm, NormFinder and BestKeeper software were used. All three gave similar results. We demonstrated that among the housekeeping genes, RPLP in SH-SY5Y and CycA and Ywhaz in PC12 are the most stable genes. Additionally, we showed that normalization with GAPDH gave misleading results compared to normalization with geNorm. In conclusion, selection of the appropriate normalization gene(s) is crucial for correct interpretation of rHuEpo treatment results. Graphical abstract

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Normalization of Gene Expression by Quantitative RT-PCR in Human Cell Line: comparison of 12 Endogenous Reference Genes

Ethiopian Journal of Health Sciences ◽

10.4314/ejhs.v28i6.9 ◽

1970 ◽

Vol 28 (6) ◽

Author(s):

Fowotade Adeola

Keyword(s):

Real Time ◽

Reference Genes ◽

Human Cell Line ◽

Optimal Number ◽

Hek293 Cells ◽

Mrna Levels ◽

Expression Stability ◽

Mrna Transcription ◽

Reliable Quantification ◽

Beta 2 Microglobulin

BACKGROUND: Polymerase Chain Reaction (PCR) has become an important diagnostic and research tool of modern molecular biology globally. Real-time PCR allows for rapid and reliable quantification of mRNA transcription. Reference genes are used as internal reaction control to normalise mRNA levels between different samples in order to allow for an exact comparison of mRNA transcription level.METHODS: In this study, twelve commonly used human reference genes were investigated in Human Embryonic Kidney Cell Lines (HEK293) using real-time qPCR with SYBR green. The genes included beta-2-microglobulin (B2M), glyceraldehyde-3- phosphate dehydrogenase (GAPDH), succinate dehydrogenase complex subunit A (SDHA), and tyrosine 3- monooxygenase/tryptophan 5-monooxygenase activation protein zeta polypeptide (YWHAZ). The stability of these reference genes was investigated using the geNorm application.RESULTS: The range of expression stability in the genes analysed was (from the most stable to the least stable): UBC, TOP1, ATP5B, CYC1, GAPDH, SDHA, YWHAZ, CTB, 18S, EIFA-2, B2M and RPL13A. The optimal number of reference targets in the experiment was calculated to be 2 (geNorm V<0.15) when comparing a normalization factor based on the 2 or 3 most stable targets).CONCLUSION: The expression stability varied greatly between the 12 candidate reference genes. UBC, TOP1, ATP5B, CYC1 and GAPDH respectively showed the highest stability in HEK293 cells based on both expression stability and expression level. Overall, our data suggest that UBC and TOP1show the least variation and the highest expression stability. This report validates the need for rational selection of reference genes for data normalization to ensure accuracy of quantitative PCR assays.

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Selection and Validation of Reference Genes for qRT-PCR in Lentinula edodes under Different Experimental Conditions

Genes ◽

10.3390/genes10090647 ◽

2019 ◽

Vol 10 (9) ◽

pp. 647 ◽

Cited By ~ 4

Author(s):

Yi Luo ◽

Gangzheng Wang ◽

Chen Wang ◽

Yuhua Gong ◽

Yinbing Bian ◽

...

Keyword(s):

Reference Gene ◽

Reference Genes ◽

Lentinula Edodes ◽

Polymerase Chain Reaction Analysis ◽

Pairwise Variation ◽

Accurate Estimation ◽

Expression Stability ◽

Experimental Conditions ◽

Qrt Pcr ◽

Accurate Normalization

Lentinula edodes is the most consumed mushroom in Asia due to its nutritional and medicinal values, and the optimal reference gene is crucial for normalization of its gene expression analysis. Here, the expression stability of 18 candidate reference genes (CRGs) in L. edodes was analyzed by three statistical algorithms (geNorm, NormFinder and BestKeeper) under different stresses (heat, cadmium excess and Trichoderma atroviride infection), different substrates (straw, sawdust and corn stalk) and different development stages (mycelia, primordia and fruit bodies). Among the 18 CRGs, 28S, Actin and α-tub exhibited the highest expression stability in L. edodes under all conditions, while GPD, SPRYP and MSF showed the least stable expression. The best reference gene in different conditions was different. The pairwise variation values showed that two genes would be sufficient for accurate normalization under different conditions of L. edodes. This study will contribute to more accurate estimation of the gene relative expression levels under different conditions using the optimal reference gene in qRT-PCR (quantitative reverse transcription polymerase chain reaction) analysis.

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Reference Gene Selection for Quantitative Real-Time PCR of Mycelia fromLentinula edodesunder High-Temperature Stress

BioMed Research International ◽

10.1155/2018/1670328 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Xu Zhao ◽

Huanling Yang ◽

Mingjie Chen ◽

Xiaoxia Song ◽

Changxia Yu ◽

...

Keyword(s):

High Temperature ◽

Real Time ◽

Temperature Stress ◽

Reference Gene ◽

Reference Genes ◽

Candidate Reference Gene ◽

Housekeeping Genes ◽

High Temperature Stress ◽

Stable Gene ◽

Mrna Levels

Housekeeping genes are important for measuring the transcription expression of functional genes; 10 traditional reference genes,TUB, TUA, GADPH, EF1, 18S, GTP, ACT, UBI, UBC,andH2A, were tested for their adequacy inLentinula edodes(L. edodes). Using specific primers, mRNA levels of these candidate housekeeping genes were evaluated in mycelia ofL. edodes, which were treated with high-temperature stress at 37°C for 0, 4, 8, 12, 18, and 24 hours. After treatment, expression stability of candidate genes was evaluated using three statistical software programs: geNorm, NormFinder, and BestKeeper. According to geNorm,TUBhad the lowest M values inL. edodesstrains 18 and 18N44. Using NormFinder, the best candidate reference gene in strain 18 wasTUB(0.030), and the best candidate reference gene in strain 18N44 wasUBI(0.047). In BestKeeper analysis, the standard deviation (SD) values ofUBC,TUA,H2A,EF1,ACT,18S, andGTPin strain 18 and those ofGADPHandGTPin strain 18N44 were greater than 1; thus, these genes were disqualified as reference genes. Taken together, onlyUBIandTUBwere found to be desirable reference genes by BestKeeper software. Based on the results of three software analyses,TUBwas the most stable gene under all conditions and was verified as an appropriate reference gene for quantitative real-time polymerase chain reaction inL. edodesmycelia under high-temperature stress.

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Evaluation of Normalization Strategies Used in Real-time Quantitative PCR Experiments in HepaRG Cell Line Studies

Clinical Chemistry ◽

10.1373/clinchem.2013.209478 ◽

2014 ◽

Vol 60 (3) ◽

pp. 451-454 ◽

Cited By ~ 11

Author(s):

Liesbeth Ceelen ◽

Jurgen De Craene ◽

Ward De Spiegelaere

Keyword(s):

Gene Expression ◽

Cell Line ◽

Real Time ◽

Reference Gene ◽

Reference Genes ◽

Heparg Cell ◽

Expression Studies ◽

Heparg Cell Line ◽

Heparg Cells ◽

Gene Expression Studies

Abstract BACKGROUND The HepaRG cell line is widely used as an alternative for primary human hepatocytes for numerous applications, including drug screening, and is progressively gaining importance as a human-relevant cell source. Consequently, increasing numbers of experiments are being performed with this cell line, including real-time quantitative PCR (RT-qPCR) experiments for gene expression studies. CONTENT When RT-qPCR experiments are performed, results are reliable only when attention is paid to several critical aspects, including a proper normalization strategy. Therefore, in 2011 we determined the most optimal reference genes for gene expression studies in the HepaRG cell system, according to the MIQE (Minimum Information for Publication of Quantitative Real-Time PCR Experiments) guidelines. This study additionally provided clear evidence that the use of a single reference gene [glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ribosomal protein S18 (RPS18), or actin, beta (ACTB)] was insufficient for normalization in HepaRG cells. Our screening of relevant studies published after our study suggested that the findings of our study were completely ignored. SUMMARY In none of the 24 reviewed studies was a proper normalization method used. Only 1 reference gene was included for normalization in 21 out of the 24 reported studies we screened, with RPS18 and GAPDH used most frequently, followed by hypoxanthine phosphoribosyltransferase 1 (HPRT1), glutathione synthetase (GSS) (hGus), β-2 microglobin (B2M), and acidic ribosomal phosphoprotein P0 (36B4). For 2 studies the use of multiple reference genes (2 and 3) was reported, but these had not been prevalidated for expression stability in HepaRG cells. In 1 study, there was no evidence that any reference gene had been used. Current RT-qPCR gene expression studies in HepaRG cells are being performed without adequate consideration or evaluation of reference genes. Such studies can yield erroneous and biologically irrelevant results.

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Optimizations for identifying reference genes in bone and cartilage bioengineering

BMC Biotechnology ◽

10.1186/s12896-021-00685-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Fei Xiong ◽

Xiangyun Cheng ◽

Chao Zhang ◽

Roland Manfred Klar ◽

Tao He

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Adipose Tissue ◽

Real Time ◽

Reference Gene ◽

Muscle Tissue ◽

Reference Genes ◽

Target Genes ◽

The Stability ◽

And Cartilage

Abstract Background Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) remains one of the best-established techniques to assess gene expression patterns. However, appropriate reference gene(s) selection remains a critical and challenging subject in which inappropriate reference gene selction can distort results leading to false interpretations. To date, mixed opinions still exist in how to choose the most optimal reference gene sets in accodrance to the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guideline. Therefore, the purpose of this study was to investigate which schemes were the most feasible for the identification of reference genes in a bone and cartilage bioengineering experimental setting. In this study, rat bone mesenchymal stem cells (rBMSCs), skeletal muscle tissue and adipose tissue were utilized, undergoing either chondrogenic or osteogenic induction, to investigate the optimal reference gene set identification scheme that would subsequently ensure stable and accurate interpretation of gene expression in bone and cartilage bioengineering. Results The stability and pairwise variance of eight candidate reference genes were analyzed using geNorm. The V0.15- vs. Vmin-based normalization scheme in rBMSCs had no significant effect on the eventual normalization of target genes. In terms of the muscle tissue, the results of the correlation of NF values between the V0.15 and Vmin schemes and the variance of target genes expression levels generated by these two schemes showed that different schemes do indeed have a significant effect on the eventual normalization of target genes. Three selection schemes were adopted in terms of the adipose tissue, including the three optimal reference genes (Opt3), V0.20 and Vmin schemes, and the analysis of NF values with eventual normalization of target genes showed that the different selection schemes also have a significant effect on the eventual normalization of target genes. Conclusions Based on these results, the proposed cut-off value of Vn/n + 1 under 0.15, according to the geNorm algorithm, should be considered with caution. For cell only experiments, at least rBMSCs, a Vn/n + 1 under 0.15 is sufficient in RT-qPCR studies. However, when using certain tissue types such as skeletal muscle and adipose tissue the minimum Vn/n + 1 should be used instead as this provides a far superior mode of generating accurate gene expression results. We thus recommended that when the stability and variation of a candidate reference genes in a specific study is unclear the minimum Vn/n + 1 should always be used as this ensures the best and most accurate gene expression value is achieved during RT-qPCR assays.

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Identification and selection of reference genes for gene expression analysis by quantitative real-time PCR in Suaeda glauca’s response to salinity

Scientific Reports ◽

10.1038/s41598-021-88151-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Meng Wang ◽

Tingting Ren ◽

Prince Marowa ◽

Haina Du ◽

Zongchang Xu

Keyword(s):

Gene Expression ◽

Real Time ◽

Reference Gene ◽

Reference Genes ◽

Suitable Reference Gene ◽

Normalize Gene Expression ◽

Suaeda Glauca ◽

Suitable Reference ◽

Germinating Seeds ◽

Different Tissues

AbstractQuantitative real-time polymerase chain reaction (qPCR) using a stable reference gene is widely used for gene expression research. Suaeda glauca L. is a succulent halophyte and medicinal plant that is extensively used for phytoremediation and extraction of medicinal compounds. It thrives under high-salt conditions, which promote the accumulation of high-value secondary metabolites. However, a suitable reference gene has not been identified for gene expression standardization in S. glauca under saline conditions. Here, 10 candidate reference genes, ACT7, ACT11, CCD1, TUA5, UPL1, PP2A, DREB1D, V-H+-ATPase, MPK6, and PHT4;5, were selected from S. glauca transcriptome data. Five statistical algorithms (ΔCq, geNorm, NormFinder, BestKeeper, and RefFinder) were applied to determine the expression stabilities of these genes in 72 samples at different salt concentrations in different tissues. PP2A and TUA5 were the most stable reference genes in different tissues and salt treatments, whereas DREB1D was the least stable. The two reference genes were sufficient to normalize gene expression across all sample sets. The suitability of identified reference genes was validated with MYB and AP2 in germinating seeds of S. glauca exposed to different NaCl concentrations. Our study provides a foundational framework for standardizing qPCR analyses, enabling accurate gene expression profiling in S. glauca.

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Expression stability of six housekeeping genes: a proposal for resistance gene quantification studies of Pseudomonas aeruginosa by real-time quantitative RT-PCR

Journal of Medical Microbiology ◽

10.1099/jmm.0.05132-0 ◽

2003 ◽

Vol 52 (5) ◽

pp. 403-408 ◽

Cited By ~ 205

Author(s):

Hakan Savli ◽

Aynur Karadenizli ◽

Fetiye Kolayli ◽

Sibel Gundes ◽

Ugur Ozbek ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Real Time ◽

Resistance Gene ◽

Housekeeping Genes ◽

Expression Stability ◽

Rt Pcr ◽

Gene Quantification

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Validation and Evaluation of Reference Genes for Quantitative Real-Time PCR in Macrobrachium Nipponense

International Journal of Molecular Sciences ◽

10.3390/ijms19082258 ◽

2018 ◽

Vol 19 (8) ◽

pp. 2258 ◽

Cited By ~ 16

Author(s):

Yuning Hu ◽

Hongtuo Fu ◽

Hui Qiao ◽

Shengming Sun ◽

Wenyi Zhang ◽

...

Keyword(s):

Real Time ◽

Reference Gene ◽

Real Time Pcr ◽

Reference Genes ◽

Translation Initiation Factor ◽

Suitable Reference Gene ◽

Quantitative Real Time Pcr ◽

Macrobrachium Nipponense ◽

The Stability ◽

Suitable Reference

Quantitative real-time PCR (qPCR) is widely used in molecular biology, although the accuracy of the quantitative results is determined by the stability of the reference genes used. Recent studies have investigated suitable reference genes for some crustaceans under various conditions, but studies in Macrobrachium nipponense are currently lacking. In this study, we selected the following seven genes from among 35 commonly used housekeeping genes as candidate qPCR reference genes for temporal and spatial expression: EIF (eukaryotic translation initiation factor 5A), 18S (18S ribosomal RNA), EF-1α (elongation factor-1α), GAPDH (glyceraldehyde-3-phosphate dehydrogenase), TUB (α-tubulin), β-act (β-actin), and RPL18 (Ribosomal protein L18). The stability of each reference gene was evaluated by GeNorm, NormFinder, BestKeeper, and comparative ∆C t methods, and was comprehensively ranked using RefFinder. RPL18 was shown to be the most suitable reference gene for adult M. nipponense tissues, while EIF was the most stable in different ovarian and embryo stages and in white spot syndrome virus infection, and β-act was the most stable reference gene under hypoxia stress. The reliability of the rankings was confirmed by RNA interference experiments. To the best of our knowledge, this represents the first systematic analysis of reference genes for qPCR experiments in M. nipponense, and the results will provide invaluable information for future research in closely related crustaceans.

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Selection and Validation of Appropriate Reference Genes for Gene Expression Studies in Schima Superba

10.21203/rs.3.rs-145449/v1 ◽

2021 ◽

Author(s):

Zhongyi Yang ◽

Rui Zhang ◽

Zhichun Zhou

Keyword(s):

Gene Expression ◽

Reference Gene ◽

Reference Genes ◽

Geometric Mean ◽

Gene Transcript ◽

Expression Stability ◽

Schima Superba ◽

Expression Studies ◽

Gene Expression Studies ◽

Different Tissues

Abstract Background Quantitative real-time PCR (qRT-PCR) is a reliable and high-throughput technique for gene expression studies, but its accuracy depends on the expression stability of reference genes. Schima superba is a strong resistance and fast-growing timber specie. However, so far, reliable reference gene identifications have not been reported in S. superba. In this study, we screened and verified the stably expressed reference genes in different tissues of S. superba.Results Nineteen candidate reference genes were selected and evaluated for their expression stability in different tissues. Three software programs (geNorm, NormFinder, and BestKeeper) were used to evaluate the reference gene transcript stabilities, and comprehensive stability ranking was generated by the geometric mean method. Our results identified that SsuACT was the most stable reference gene, SsuACT + SsuRIB was the best reference genes combination for different tissues. Finally, the stable and less stable reference genes were verified using the SsuSND1 expression in different tissues.Conclusions This is the first report to verify the appropriate reference genes for normalizing gene expression in S. superba for different tissues, which will facilitate future elucidation of gene regulations in this species, and useful references for relative species.

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