Optimizations for identifying reference genes in bone and cartilage bioengineering

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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Optimizations for Identifying Reference Genes in Bone and Cartilage Bioengineering

10.21203/rs.3.rs-96393/v1 ◽

2020 ◽

Author(s):

Fei Xiong ◽

Xiangyun Cheng ◽

Chao Zhang ◽

Roland Manfred Klar ◽

Tao He

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Adipose Tissue ◽

Reference Gene ◽

Muscle Tissue ◽

Reference Genes ◽

Target Genes ◽

Gene Set ◽

The Stability ◽

And Cartilage

Abstract Background：Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is commonly considered as the best-established technique for gene expression assay. However, appropriate reference gene set selection remains the critical and challenging subject for the proper understanding of gene expression pattern. Mixed opinions pertain in how to choose optimal reference gene set according 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 was the most feasible for the identification of reference genes in bone and cartilage bioengineering experiments. 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 ensuring the 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 different schemes may 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 and eventual normalization of target genes showed that the different selection schemes have significant effect on the eventual normalization of target genes.Conclusions：Based on the results, the proposed cut-off value of Vn/n+1 under 0.15, according to geNorm algorithm, should be considered with caution, especially in certain tissue types such as skeletal muscle and adipose tissue. Instead, the minimum Vn/n+1 should be used as the cut-off for choosing the optimal reference gene set especially when the stability and variation of candidate reference genes in a specific study are unclear.

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Evaluation of reference genes for gene expression studies in pig muscle tissue by real-time PCR

Czech Journal of Animal Science ◽

10.17221/1428-cjas ◽

2011 ◽

Vol 56 (No. 5) ◽

pp. 213-216 ◽

Cited By ~ 2

Author(s):

M. Nesvadbová ◽

A. Knoll

Keyword(s):

Gene Expression ◽

Real Time ◽

Reference Gene ◽

Muscle Tissue ◽

Reference Genes ◽

Expression Profiles ◽

Quantitative Polymerase Chain Reaction ◽

Expression Studies ◽

Gene Expression Studies ◽

The Stability

The selection of reference genes is essential for gene expression studies when using a real-time quantitative polymerase chain reaction (PCR). Reference gene selection should be performed for each experiment because the gene expression level may be changed in different experimental conditions. In this study, the stability of mRNA expression was determined for seven genes: HPRT1, RPS18, NACA, TBP, TAF4B, RPL32 and OAZ1. The stability of these reference genes was investigated in the skeletal muscle tissue of pig foetuses, piglets and adult pigs using real-time quantitative PCR and SYBR green chemistry. The expression of stability of the used reference genes was calculated using the geNorm application. Different gene expression profiles among the age categories of pigs were found out. RPS18 has been identified as the gene with the most stable expression in the muscle tissue of all pig age categories. HPRT1 and RPL32 were found to have the highest stability in piglets and adult pigs, and in foetuses and adults pigs, respectively. The newly used reference gene, TAF4B, reached the highest expression stability in piglets.

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Selection and validation of reference genes by RT-qPCR under photoperiodic induction of flowering in sugarcane (Saccharum spp.)

Scientific Reports ◽

10.1038/s41598-021-83918-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Paulo H. da Silva Santos ◽

João R. Vieira Manechini ◽

Michael S. Brito ◽

Elisson Romanel ◽

Renato Vicentini ◽

...

Keyword(s):

Gene Expression ◽

Reference Gene ◽

Reference Genes ◽

Target Genes ◽

Floral Induction ◽

Photoperiodic Induction ◽

Experimental Conditions ◽

Wide Range ◽

The Stability ◽

Stability And Consistency

AbstractAlthough reference genes have previously been used in the expression analysis of genes involved in sugarcane flowering they had not been experimentally validated for stability and consistency of expression between different samples over a wide range of experimental conditions. Here we report the analysis of candidate reference genes in different tissue types, at different temporal time-points, in both short and long day photoperiodic treatments. The stability of the candidate reference genes in all conditions was evaluated with NormFinder, BestKeeper, and RefFinder algorithms that complement each other for a more robust analysis. As the Normfinder algorithm was more appropriate for our experimental conditions, greater emphasis was placed on Normfinder when choosing the most stable genes. UBQ1 and TUB were shown to be the most stable reference genes to use for normalizing RT-qPCR gene expression data during floral induction, whilst 25SrRNA1 and GAPDH were the least stable. Their use as a reference gene pair was validated by analyzing the expression of two differentially expressed target genes (PIL5 and LHP1). The UBQ1/TUB reference genes combination was able to reveal small significant differences in gene expression of the two target genes that were not detectable when using the least stable reference gene combination. These results can be used to inform the choice of reference genes to use in the study of the sugarcane floral induction pathway. Our work also demonstrates that both PIL5 and LHP1 are significantly up-regulated in the initial stages of photoperiodic induction of flowering in sugarcane.

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Current Practices for Reference Gene Selection in RT-qPCR of Aspergillus: Outlook and Recommendations for the Future

Genes ◽

10.3390/genes12070960 ◽

2021 ◽

Vol 12 (7) ◽

pp. 960

Author(s):

Meagan Archer ◽

Jianping Xu

Keyword(s):

Gene Expression ◽

Reference Gene ◽

Reference Genes ◽

Gene Selection ◽

Quantitative Polymerase Chain Reaction ◽

Specific Method ◽

Experimental Conditions ◽

Reference Gene Selection ◽

Physiological Processes ◽

The Stability

Aspergillus is a genus of filamentous fungi with vast geographic and ecological distributions. Species within this genus are clinically, agriculturally and biotechnologically relevant, leading to increasing interest in elucidating gene expression dynamics of key metabolic and physiological processes. Reverse-transcription quantitative Polymerase Chain Reaction (RT-qPCR) is a sensitive and specific method of quantifying gene expression. A crucial step for comparing RT-qPCR results between strains and experimental conditions is normalisation to experimentally validated reference gene(s). In this review, we provide a critical analysis of current reference gene selection and validation practices for RT-qPCR gene expression analyses of Aspergillus. Of 90 primary research articles obtained through our PubMed query, 17 experimentally validated the reference gene(s) used. Twenty reference genes were used across the 90 studies, with beta-tubulin being the most used reference gene, followed by actin, 18S rRNA and glyceraldehyde 3-phosphate dehydrogenase. Sixteen of the 90 studies used multiple reference genes for normalisation. Failing to experimentally validate the stability of reference genes can lead to conflicting results, as was the case for four studies. Overall, our review highlights the need to experimentally validate reference genes in RT-qPCR studies of Aspergillus.

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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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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 reference genes for quantitative gene expression analyses in persimmon (Diospyros kaki Thunb.) using real-time quantitative PCR

Biologia Futura ◽

10.1556/019.70.2019.24 ◽

2019 ◽

Vol 70 (4) ◽

pp. 261-267

Author(s):

Gaigai Du ◽

Liyuan Wang ◽

Huawei Li ◽

Peng Sun ◽

Jianmin Fu ◽

...

Keyword(s):

Gene Expression ◽

Real Time ◽

Reference Gene ◽

Reference Genes ◽

Developmental Stages ◽

Suitable Reference Gene ◽

Diospyros Kaki ◽

Stable Gene ◽

Expression Studies ◽

Gene Expression Studies

Background and aims Persimmon (Diospyros kaki) is an economically important fruit tree species with complex flowering characteristics. To obtain accurate expression pattern analysis results, it is vital to select a reliable gene for the normalization of real-time quantitative polymerase chain reaction data. The aim of this study was to identify the optimal internal control gene among six candidate genes for gene expression analysis in different persimmon organs and developmental stages. Materials and methods This analysis was conducted using geNorm and NormFinder software to show differences in the stability of the six reference genes among tissues and floral developmental stages of the same plant. Results Although genes that exhibited moderate expression in NormFinder revealed slightly different expression stabilities than those obtained by geNorm, both sets of results showed that GAPDH was the best reference gene in different organs and floral buds at different developmental stages, whereas 18SrRNA was the least stable gene. Conclusions Based on the overall ranking, GAPDH is the most suitable reference gene and is highly recommended for gene expression studies in different organs and different developmental stages of persimmon. This study provides useful reference data for future gene expression studies and will contribute to improving the accuracy of gene expression results in persimmon.

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Evaluation of putative reference genes for quantitative real-time PCR normalization inLilium regaleduring development and under stress

PeerJ ◽

10.7717/peerj.1837 ◽

2016 ◽

Vol 4 ◽

pp. e1837 ◽

Cited By ~ 15

Author(s):

Qiang Liu ◽

Chi Wei ◽

Ming-Fang Zhang ◽

Gui-Xia Jia

Keyword(s):

Gene Expression ◽

Heat Stress ◽

Real Time ◽

Quantitative Pcr ◽

Biotic Stress ◽

Reference Genes ◽

Developmental Stages ◽

Real Time Quantitative Pcr ◽

The Stability ◽

Experimental Treatments

Normalization to reference genes is the most common method to avoid bias in real-time quantitative PCR (qPCR), which has been widely used for quantification of gene expression. Despite several studies on gene expression,Lilium, and particularlyL. regale, has not been fully investigated regarding the evaluation of reference genes suitable for normalization. In this study, nine putative reference genes, namely18S rRNA,ACT,BHLH,CLA,CYP,EF1,GAPDH,SANDandTIP41, were analyzed for accurate quantitative PCR normalization at different developmental stages and under different stress conditions, including biotic (Botrytis elliptica), drought, salinity, cold and heat stress. All these genes showed a wide variation in their Cq (quantification Cycle) values, and their stabilities were calculated by geNorm, NormFinder and BestKeeper. In a combination of the results from the three algorithms,BHLHwas superior to the other candidates when all the experimental treatments were analyzed together;CLAandEF1were also recommended by two of the three algorithms. As for specific conditions,EF1under various developmental stages,SANDunder biotic stress,CYP/GAPDHunder drought stress, andTIP41under salinity stress were generally considered suitable. All the algorithms agreed on the stability ofSANDandGAPDHunder cold stress, while onlyCYPwas selected under heat stress by all of them. Additionally, the selection of optimal reference genes under biotic stress was further verified by analyzing the expression level ofLrLOXin leaves inoculated withB. elliptica. Our study would be beneficial for future studies on gene expression and molecular breeding ofLilium.

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Identification and Validation of Reference Genes for Gene Expression Analysis in Different Development Stages of Amylostereum areolatum

Frontiers in Microbiology ◽

10.3389/fmicb.2021.827241 ◽

2022 ◽

Vol 12 ◽

Author(s):

Ningning Fu ◽

Jiaxing Li ◽

Ming Wang ◽

Lili Ren ◽

Shixiang Zong ◽

...

Keyword(s):

Gene Expression ◽

Reference Genes ◽

Growth And Development ◽

Target Genes ◽

Quantitative Polymerase Chain Reaction ◽

Growth Stages ◽

Experimental Conditions ◽

Development Stages ◽

Symbiotic Fungus ◽

The Stability

A strict relationship exists between the Sirex noctilio and the Amylostereum areolatum, which is carried and spread by its partner. The growth and development of this symbiotic fungus is key to complete the life history of the Sirex woodwasp. Real-time quantitative polymerase chain reaction (RT-qPCR) is used to measure gene expression in samples of A. areolatum at different growth stages and explore the key genes and pathways involved in the growth and development of this symbiotic fungus. To obtain accurate RT-qPCR data, target genes need to be normalized by reference genes that are stably expressed under specific experimental conditions. In our study, the stability of 10 candidate reference genes in symbiotic fungal samples at different growth and development stages was evaluated using geNorm, NormFinder, BestKeeper, delta Ct methods, and RefFinder. Meanwhile, laccase1 was used to validate the stability of the selected reference gene. Under the experimental conditions of this study, p450, CYP, and γ-TUB were identified as suitable reference genes. This work is the first to systematically evaluate the reference genes for RT-qPCR results normalization during the growth of this symbiotic fungus, which lays a foundation for further gene expression experiments and understanding the symbiotic relationship and mechanism between S. noctilio and A. areolatum.

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Stability of Nuclear and Mitochondrial Reference Genes in Selected Tissues of the Ambrosia Beetle Xylosandrus germanus

Insects ◽

10.3390/insects12121125 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1125

Author(s):

Nisha Patwa ◽

Christopher M. Ranger ◽

Maximilian Lehenberger ◽

Peter H. Biedermann ◽

Michael E. Reding

Keyword(s):

Gene Expression ◽

Reference Gene ◽

Reference Genes ◽

Target Genes ◽

Ambrosia Beetle ◽

Whole Body ◽

28S Rrna ◽

Carbamoyl Phosphate ◽

Aspartate Transcarbamylase ◽

Xylosandrus Germanus

The fungus-farming ambrosia beetle Xylosandrus germanus (Blandford) uses a pouch-like structure (i.e., mycangium) to transport spores of its nutritional fungal mutualist. Our current study sought to identify reference genes necessary for future transcriptome analyses aimed at characterizing gene expression within the mycangium. Complementary DNA was synthesized using selected tissue types from laboratory-reared and field-collected X. germanus consisting of the whole body, head + thorax, deflated or inflated mycangium + scutellum, inflated mycangium, and thorax + abdomen. Quantitative reverse-transcription PCR reactions were performed using primers for 28S ribosomal RNA (28S rRNA), arginine kinase (AK), carbamoyl-phosphate synthetase 2-aspartate transcarbamylase-dihydroorotase (CAD), mitochondrial cytochrome oxidase 1 (CO1), and elongation factor-1α (EF1α). Reference gene stability was analyzed using GeNorm, NormFinder, BestKeeper, ΔCt, and a comprehensive final ranking by RefFinder. The gene CO1 was identified as the primary reference gene since it was generally ranked in first or second position among the tissue types containing the mycangium. Reference gene AK was identified as a secondary reference gene. In contrast, EF1α was generally ranked in the last or penultimate place. Identification of two stable reference genes will aid in normalizing the expression of target genes for subsequent gene expression studies of X. germanus’ mycangium.

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