Dataset Information

Screening for Suitable Reference Genes for Quantitative Real-Time PCR in Heterosigma akashiwo (Raphidophyceae).

ABSTRACT: The raphidophyte Heterosigma akashiwo is a globally distributed harmful alga that has been associated with fish kills in coastal waters. To understand the mechanisms of H. akashiwo bloom formation, gene expression analysis is often required. To accurately characterize the expression levels of a gene of interest, proper reference genes are essential. In this study, we assessed ten of the previously reported algal candidate genes (rpL17-2, rpL23, cox2, cal, tua, tub, ef1, 18S, gapdh, and mdh) for their suitability as reference genes in this species. We used qRT-PCR to quantify the expression levels of these genes in H. akashiwo grown under different temperatures, light intensities, nutrient concentrations, and time points over a diel cycle. The expression stability of these genes was evaluated using geNorm and NormFinder algorithms. Although none of these genes exhibited invariable expression levels, cal, tub, rpL17-2 and rpL23 expression levels were the most stable across the different conditions tested. For further validation, these selected genes were used to normalize the expression levels of ribulose-1, 5-bisphosphate carboxylase/oxygenase large unite (HrbcL) over a diel cycle. Results showed that the expression of HrbcL normalized against each of these reference genes was the highest at midday and lowest at midnight, similar to the diel patterns typically documented for this gene in algae. While the validated reference genes will be useful for future gene expression studies on H. akashiwo, we expect that the procedure used in this study may be helpful to future efforts to screen reference genes for other algae.

SUBMITTER: Ji N

PROVIDER: S-EPMC4489630 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Screening for Suitable Reference Genes for Quantitative Real-Time PCR in Heterosigma akashiwo (Raphidophyceae).

Ji Nanjing N Li Ling L Lin Lingxiao L Lin Senjie S

PloS one 20150702 7

The raphidophyte Heterosigma akashiwo is a globally distributed harmful alga that has been associated with fish kills in coastal waters. To understand the mechanisms of H. akashiwo bloom formation, gene expression analysis is often required. To accurately characterize the expression levels of a gene of interest, proper reference genes are essential. In this study, we assessed ten of the previously reported algal candidate genes (rpL17-2, rpL23, cox2, cal, tua, tub, ef1, 18S, gapdh, and mdh) for ...[more]

PMID: 26133173

Similar Datasets

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:BackgroundMaintenance of homeostasis requires that an organism perceive selected physical and chemical signals within an informationally dense environment. Functionally, an organism uses a variety of signal transduction arrays to amplify and convert these perceived signals into appropriate gene transcriptional responses. These changes in gene expression serve to modify selective metabolic processes and thus optimize reproductive success. Here we analyze a chloroplast-encoded His-to-Asp signal transduction circuit in the stramenopile Heterosigma akashiwo (Hada) Hada ex Y. Hara et Chihara [syn. H. carterae (Hulburt) F.J.R. Taylor]. The presence, structure and putative function of this protein pair are discussed in the context of their evolutionary homologues.ResultsBioinformatic analysis of the Heterosigma akashiwo chloroplast genome sequence revealed the presence of a single two-component His-to-Asp (designated Tsg1/Trg1) pair in this stramenopile (golden-brown alga). These data represent the first documentation of a His-to-Asp array in stramenopiles and counter previous reports suggesting that such regulatory proteins are lacking in this taxonomic cluster. Comparison of the 43 kDa H. akashiwo Tsg1 with bacterial sensor kinases showed that the algal protein exhibits a moderately maintained PAS motif in the sensor kinase domain as well as highly conserved H, N, G1 and F motifs within the histidine kinase ATP binding site. Molecular modelling of the 27 kDa H. akashiwo Trg1 regulator protein was consistent with a winged helix-turn-helix identity - a class of proteins that is known to impact gene expression at the level of transcription. The occurrence of Trg1 protein in actively growing H. akashiwo cells was verified by Western analysis. The presence of a PhoB-like RNA polymerase loop in Trg1 and its homologues in the red-algal lineage support the hypothesis that Trg1 and its homologues interact with a sigma 70 (sigma70) subunit (encoded by rpoD) of a eubacterial type polymerase. Sequence analysis of H. akashiwo rpoD showed this nuclear-encoded gene has a well-defined 4.2 domain, a region that augments RNA polymerase interaction with transcriptional regulatory proteins and also serves in -35 promoter recognition. The presence/loss of the His-to-Asp pairs in primary and secondary chloroplast lineages is assessed.ConclusionHis-to-Asp signal transduction components are found in most rhodophytic chloroplasts, as well as in their putative cyanobacterial progenitors. The evolutionary conservation of these proteins argues that they are important for the maintenance of chloroplast homeostasis. Our data suggest that chloroplast gene transcription may be impacted by the interaction of the His-to-Asp regulator protein (which is less frequently lost than the sensor protein) with the RNA polymerase sigma70 subunit.

Dataset Information

Screening for Suitable Reference Genes for Quantitative Real-Time PCR in Heterosigma akashiwo (Raphidophyceae).

Publications

Screening for Suitable Reference Genes for Quantitative Real-Time PCR in Heterosigma akashiwo (Raphidophyceae).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets