Dataset Information

The evaluation of anoxia responsive E2F DNA binding activity in the red eared slider turtle, Trachemys scripta elegans.

ABSTRACT: In many cases, the DNA-binding activity of a transcription factor does not change, while its transcriptional activity is greatly influenced by the make-up of bound proteins. In this study, we assessed the protein composition and DNA-binding ability of the E2F transcription factor complex to provide insight into cell cycle control in an anoxia tolerant turtle through the use of a modified ELISA protocol. This modification also permits the use of custom DNA probes that are tailored to a specific DNA binding region, introducing the ability to design capture probes for non-model organisms. Through the use of EMSA and ELISA DNA binding assays, we have successfully determined the in vitro DNA binding activity and complex dynamics of the Rb/E2F cell cycle regulatory mechanisms in an anoxic turtle, Trachemys scripta elegans. Repressive cell cycle proteins (E2F4, Rb, HDAC4 and Suv39H1) were found to significantly increase at E2F DNA-binding sites upon anoxic exposure in anoxic turtle liver. The lack of p130 involvement in the E2F DNA-bound complex indicates that anoxic turtle liver may maintain G1 arrest for the duration of stress survival.

SUBMITTER: Biggar KK

PROVIDER: S-EPMC5951122 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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The evaluation of anoxia responsive E2F DNA binding activity in the red eared slider turtle, <i>Trachemys scripta elegans</i>.

Biggar Kyle K KK Storey Kenneth B KB

PeerJ 20180511

In many cases, the DNA-binding activity of a transcription factor does not change, while its transcriptional activity is greatly influenced by the make-up of bound proteins. In this study, we assessed the protein composition and DNA-binding ability of the E2F transcription factor complex to provide insight into cell cycle control in an anoxia tolerant turtle through the use of a modified ELISA protocol. This modification also permits the use of custom DNA probes that are tailored to a specific D ...[more]

PMID: 29770276

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Project description:The red-eared slider (Trachemys scripta elegans), identified as one of the 100 most invasive species in the world, is a freshwater turtle originally from the eastern United States and northeastern Mexico. Field investigations have shown that T. s. elegans can survive and lay eggs in saline habitats. In order to understand the molecular mechanisms of salinity adaptation, high-throughput RNA-Seq was utilized to identify the changes in gene expression profiles in the liver of T. s. elegans in response to elevated salinity. We exposed individuals to 0, 5, or 15 psu (practical salinity units) for 30 days. A total of 157.21 million reads were obtained and assembled into 205138 unigenes with an average length of 620 bp and N50 of 964 bp. Of these, 1019 DEGs (differentially expressed genes) were found in the comparison of 0 vs. 5 psu, 1194 DEGs in 0 vs. 15 psu and 1180 DEGs in 5 vs. 15 psu, which are mainly related to macromolecule metabolic process, ion transport, oxidoreductase activity and generation of precursor metabolites and energy by GO (Gene Ontology) enrichment analyses. T. s. elegans can adapt itself into salinity by balancing the entry of sodium and chloride ions via the up-regulation expression genes of ion transport (potassium voltage-gated channel subfamily H member 5, KCNH5; erine/threonine-protein kinase 32, STK32; salt-inducible kinase 1, SIK1; adiponectin, ACDC), and by accumulating plasma urea and free amino acid via the up-regulation expression genes of amino acid metabolism (ornithine decarboxylase antizyme 3, OAZ3; glutamine synthetase, GLUL; asparaginase-like protein 1b, ASRGL; L-amino-acid oxidase-like, LAAO; sodium-dependent neutral amino acid transporter B, SLC6A15s; amino acid permease, SLC7A9) in response to osmotic regulation. An investment of energy to maintain their homeostatic balance is required to salinity adaptation, therefore, the genes related to energy production and conversion (F-ATPase protein 6, ATP6; cytochrome c oxidase subunit I, COX1; cytochrome c oxidase subunit III, COX3; cytochrome b, CYTb; cytochrome P450 17A1, CYP17A1) were up-regulated with the increase of gene expression associated with lipid metabolism (apolipoprotein E precursor, APoE; coenzyme Q-binding protein, CoQ10; high-density lipoprotein particle, SAA) and carbohydrate metabolism (HK, MIP). These findings improve our understanding of the underlying molecular mechanisms involved in salinity adaptation and provide general guidance to illuminate the invasion potential of T. s. elegans into saline environments.

Project description:Aquatic animals have developed various mechanisms to live in either hyperionic or hypoionic environments, and, as such, not many species are capable of surviving in both. The red-eared slider turtle, Trachemys scripta elegans, a well-known freshwater species, has recently been found to invade and inhabit brackish water. Herein, we focus on some of the metabolic adaptations that are required to survive and cope with salinity stress. The regulation of the adenosine monophosphate (AMP)-activated protein kinase (AMPK), a main cellular "energy sensor," and its influence on lipid metabolism were evaluated with a comparison of three groups of turtles: controls in freshwater, and turtles held in water of either 5‰ salinity (S5) or 15‰ salinity (S15) with sampling at 6, 24, and 48 h and 30 days of exposure. When subjected to elevated salinities of 5 or 15‰, AMPK mRNA levels and AMPK enzyme activity increased strongly. In addition, the high expression of the peroxisome proliferator activated receptor-α (PPARα) transcription factor that, in turn, facilitated upregulation of target genes including carnitine palmitoyltransferase (CPT) and acyl-CoA oxidase (ACO). Furthermore, the expression of transcription factors involved in lipid synthesis such as the carbohydrate-responsive element-binding protein (ChREBP) and sterol regulatory element-binding protein 1c (SREBP-1c) was inhibited, and two of their target genes, acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), were significantly decreased. Moreover, exposure to saline environments also increased plasma triglyceride (TG) content. Interestingly, the content of low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) in plasma was markedly higher than the control in the S15 group after 30 days, which indicated that lipid metabolism was disrupted by chronic exposure to high salinity. These findings demonstrate that activation of AMPK might regulate lipid metabolism in response to salinity stress through the inhibition of lipid synthesis and promotion of lipid oxidation in the liver of T. s. elegans. This may be an important component of the observed salinity tolerance of these turtles that allow for invasion of brackish waters.

Dataset Information

The evaluation of anoxia responsive E2F DNA binding activity in the red eared slider turtle, Trachemys scripta elegans.

Publications

The evaluation of anoxia responsive E2F DNA binding activity in the red eared slider turtle, <i>Trachemys scripta elegans</i>.

Similar Datasets

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