A method to quantitate maternal transcripts localized in sea urchin egg cortex by RT-qPCR with accurate normalization

The sea urchin egg cortex is a peripheral region of eggs consisting of cell membrane and adjacent cytoplasm, which contains actin and tubulin cytoskeleton, cortical granules and some proteins required for early development. Method for isolation of cortices from sea urchin eggs and early embryos has been developed in 70s of 20th Century. Since that time this method has been reliable tool to study protein localization and cytoskeletal organization in cortex of unfertilized eggs and embryos during first cleavages. This study is an estimation of reliability of RT-qPCR to analyze levels of maternal transcripts that are localized in egg cortex. Firstly, we selected seven potential reference genes, 28S, Cycb , Ebr1 , GAPDH , Hmg1 , Smtnl1 and Ubb , which transcripts are maternally deposited in sea urchin eggs. The candidate reference genes were ranked by five different algorithms (BestKeeper, CV, ΔCt, geNorm and NormFinder) upon calculated level stability in both eggs and isolated cortices. Our results show that gene ranking differs in total RNA and mRNA samples, though Ubb is most suitable reference gene in both cases. To validate feasibility of comparative analysis of eggs and isolated egg cortices by RT-qPCR, we selected Daglb-2 as a gene of interest, which transcripts potentially localized in cortex, and found increased level of Daglb -2 in egg cortices. This suggests that proposed RNA isolation method with subsequent quantitative RT-qPCR analysis can be used to approve cortical association of transcripts in sea urchin eggs.

Selection of the reference genes for quantitative gene expression by RT-qPCR in the desert plant Stipagrostis pennata

The desert pioneer plant Stipagrostis pennata plays an important role in sand fixation, wind prevention, and desert ecosystem recovery. An absence of reference genes greatly limits investigations into the regulatory mechanism by which S. pennata adapts to adverse desert environments at the molecular and genetic levels. In this study, eight candidate reference genes were identified from rhizosheath development transcriptome data from S. pennata, and their expression stability in the rhizosheaths at different development stages, in a variety of plant tissues, and under drought stress was evaluated using four procedures, including geNorm, NormFinder, BestKeeper, and RefFinder. The results showed that GAPDH and elF were the most stable reference genes under drought stress and in rhizosheath development, and ARP6 and ALDH were relatively stable in all plant tissues. In addition, elF was the most suitable reference gene for all treatments. Analysis of the consistency between the reverse transcription-quantitative PCR (RT-qPCR) and RNA sequencing data showed that the identified elF and GAPDH reference genes were stable during rhizosheath development. These results provide reliable reference genes for assuring the accuracy of RT-qPCR and offer a foundation for further investigations into the genetic responses of S. pennata to abiotic stress.

Selection and stability validation of reference gene candidates for transcriptional analysis in Rousettus aegyptiacus

Bats are the only mammals capable of powered flight and their body temperature can reach up to 42 °C during flight. Additionally, bats display robust type I IFN interferon (IFN-I) responses and some species constitutively express IFN-α. Reference genes with stable expression under temperature oscillations and IFN-I release are therefore critical for normalization of quantitative reverse-transcription polymerase chain reaction (qRT-PCR) data in bats. The expression stability of reference genes in Rousettus aegyptiacus remains elusive, although this species is frequently used in the infection research. We selected ACTB, EEF1A1, GAPDH and PGK1 as candidate reference genes and evaluated their expression stability in various tissues and cells from this model bat species upon IFN-I treatment at 35 °C, 37 °C and 40 °C by qRT-PCR. We employed two statistical algorithms, BestKeeper and NormFinder, and found that EEF1A1 exhibited the highest expression stability under all tested conditions. ACTB and GAPDH displayed unstable expression upon temperature change and IFN-I treatment, respectively. By normalizing to EEF1A1, we uncovered that GAPDH expression was significantly induced by IFN-I in R. aegyptiacus. Our study identifies EEF1A1 as the most suitable reference gene for qRT-PCR studies upon temperature changes and IFN-I treatment and unveils the induction of GAPDH expression by IFN-I in R. aegyptiacus. These findings are pertinent to other bat species and may be relevant for non-volant mammals that show physiological fluctuations of core body temperature.

Identification of the most suitable reference gene for gene expression studies with development and abiotic stress response in Bromus sterilis

Bromus sterilis is an annual weedy grass, causing high yield losses in winter cereals. Frequent use of herbicides had led to the evolution of herbicide resistance in this species. Mechanisms underlying herbicide resistance in B. sterilis must be uncovered because this problem is becoming a global threat. qRT-PCR and the next-generation sequencing technologies can elucidate the resistance mechanisms. Although qRT-PCR can calculate precise fold changes, its preciseness depends on the expression of reference genes. Regardless of stable expression in any given condition, no gene can act as a universal reference gene. Hence, it is necessary to identify the suitable reference gene for each species. To our knowledge, there are no reports on the suitable reference gene in any brome species so far. Thus, in this paper, the stability of eight genes was evaluated using qRT-PCR experiments followed by expression stability ranking via five most commonly used software for reference gene selection. Our findings suggest using a combination of 18S rRNA and ACCase to normalise the qRT-PCR data in B. sterilis. Besides, reference genes are also recommended for different experimental conditions. The present study outcomes will facilitate future molecular work in B. sterilis and other related grass species.

Selection and Stability Validation of Reference Gene Candidates for Transcriptional Analysis in Rousettus Aegyptiacus

Bats are the only mammals capable of powered flight and their body temperature can reach up to 42°C during flight. Additionally, bats display robust type I IFN interferon (IFN-I) responses and some species constitutively express IFN-α. Reference genes with stable expression under temperature oscillations and IFN-I release are therefore critical for normalization of quantitative reverse-transcription polymerase chain reaction (qRT-PCR) data in bats. The expression stability of reference genes in Rousettus aegyptiacus remains elusive, although this species is frequently used in the infection research. We selected ACTB, EEF1A1, GAPDH and PGK1 as candidate reference genes and evaluated their expression stability in various tissues and cells from this model bat species upon IFN-I treatment at 37°C and 40°C by qRT-PCR. We employed two statistical algorithms, BestKeeper and NormFinder, and found that EEF1A1 exhibited the highest stability under all tested conditions. ACTB and GAPDH displayed unstable expression at 40°C and upon IFN-I treatment, respectively. By normalizing to EEF1A1, we uncovered that GAPDH expression was significantly induced by IFN‑I in R. aegyptiacus. Our study identifies EEF1A1 as the most suitable reference gene for qRT-PCR studies and unveils the induction of GAPDH expression by IFN-I in R. aegyptiacus. These findings are pertinent to other bat species and even bear relevance for non-volant mammals that show physiological fluctuations of core body temperature.

miR-361-5p as a promising qRT-PCR internal control for tumor and normal breast tissues

Background One of the most widely used evaluation methods in miRNA experiments is qRT-PCR. However, selecting suitable internal controls (IC) is crucial for qRT-PCR experiments. Currently, there is no consensus on the ICs for miRNA qRT-PCR experiments in breast cancer. To this end, we tried to identify the most stable (the least expression alteration) and promising miRNAs in normal and tumor breast tissues by employing TCGA miRNA-Seq data and then experimentally validated them on fresh clinical samples. Methods A multi-component scoring system was used which takes into account multiple expression stability criteria as well as correlation with clinical characteristics. Furthermore, we extended the scoring system for more than two biological sub-groups. TCGA BRCA samples were analyzed based on two grouping criteria: Tumor & Normal samples and Tumor subtypes. The top 10 most stable miRNAs were further investigated by differential expression and survival analysis. Then, we examined the expression level of the top scored miRNA (hsa-miR-361-5p) along with two commonly used ICs hsa-miR-16-5p and U48 on 34 pairs of Primary breast tumor and their adjacent normal tissues using qRT-PCR. Results According to our multi-component scoring system, hsa-miR-361-5p had the highest stability score in both grouping criteria and hsa-miR-16-5p showed significantly lower scores. Based on our qRT-PCR assay, while U48 was the most abundant IC, hsa-miR-361-5p had lower standard deviation and also was the only IC capable of detecting a significant up-regulation of hsa-miR-21-5p in breast tumor tissue. Conclusions miRNA-Seq data is a great source to discover stable ICs. Our results demonstrated that hsa-miR-361-5p is a highly stable miRNA in tumor and non-tumor breast tissue and we recommend it as a suitable reference gene for miRNA expression studies in breast cancer. Additionally, although hsa-miR-16-5p is a commonly used IC, it’s not a suitable one for breast cancer studies.

Selection of a reference gene for studies of adipose tissues of toothed whales

Fat metabolism in toothed whales is different from other mammals. RT-qPCR is still a reliable technique for studying the relative expressions of various genes involved in metabolism. This study was done for Risso’s dolphin, a toothed whale and information produced here will be important for further transcriptomics studies focused on unrevealed marine mammal fat metabolism. In this study, we sought to identify a suitable reference gene with minimum resources. Seven candidate reference genes ZC3H10, FTL, LGALS1, RPL27A, GAPDH, FTH1 and DCN were initially tested for amplification efficiency using RT-qPCR by producing standard curves. Then, three nearly 100% efficient genes FTL, LGALS1 and GAPDH were selected for the gene stability analysis to determine one stable gene across eight different fat tissues, liver, and muscle of Risso’s dolphins based on four algorithms, provided in geNorm, NormFinder, BestKeeper and Delta Ct. Finally, a RefFinder comprehensive ranking was done based on stability values and the genes were ranked as: FTL>LGALS1>GAPDH. The FTL and LGHLS were identified as the most stable genes; however, GAPDH was third, a well-known housekeeping gene for mammals. Finally, we suggest using FTL as a reliable reference gene for functional genomics studies on toothed whales in the future.

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

Quantitative 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.

Reference gene selection for expression studies in the reproductive axis tissues of Magang geese at different reproductive stages under light treatment

In quantitative PCR research, appropriate reference genes are key to determining accurate mRNA expression levels. In order to screen the reference genes suitable for detecting gene expression in tissues of the reproductive axis, a total of 420 (males and females = 1:5) 3-year-old Magang geese were selected and subjected to light treatment. The hypothalamus, pituitary and testicular tissues were subsequently collected at different stages. Ten genes including HPRT1, GAPDH, ACTB, LDHA, SDHA, B2M, TUBB4, TFRC, RPS2 and RPL4 were selected as candidate reference genes. The expression of these genes in goose reproductive axis tissues was detected by real-time fluorescent quantitative PCR. The ΔCT, geNorm, NormFinder and BestKeeper algorithms were applied to sort gene expression according to stability. The results showed that ACTB and TUBB4 were the most suitable reference genes for the hypothalamic tissue of Magang goose in the three breeding stages; HPRT1 and RPL4 for pituitary tissue; and HPRT1 and LDHA for testicular tissue. For all three reproductive axis tissues, ACTB was the most suitable reference gene, whereas the least stable reference gene was GAPDH. Altogether, these results can provide references for tissue expression studies in geese under light treatment.