In higher metazoans, the nuclear hormone receptors activate transcription trough their specific adaptors, nuclear hormone receptor adaptors NCoA, which are absent in lower metazoans. The Nine amino acid TransActivation Domain, 9aaTAD, was reported for a large number of the transcription activators that recruit general mediators of transcription. In this study, we demonstrated that the 9aaTAD from NHR-49 receptor of nematode C.elegans activates transcription as a small peptide. We showed that the ancient 9aaTAD domains are conserved in the nuclear hormone receptors including human HNF4, RARa, VDR and PPARg. Also their small 9aaTAD peptides effectively activated transcription in absence of the NCoA adaptors. We also showed that adjacent H11 domains in ancient and modern hormone receptors have an inhibitory effect on their 9aaTAD function.
- MeSH
- aktivace transkripce * MeSH
- alfa receptor kyseliny retinové chemie metabolismus MeSH
- Caenorhabditis elegans chemie metabolismus MeSH
- hepatocytární jaderný faktor 4 chemie metabolismus MeSH
- lidé MeSH
- molekulární modely MeSH
- peptidy chemie metabolismus MeSH
- PPAR gama chemie metabolismus MeSH
- proteinové domény MeSH
- proteiny Caenorhabditis elegans chemie metabolismus MeSH
- receptory cytoplazmatické a nukleární chemie metabolismus MeSH
- receptory kalcitriolu chemie metabolismus MeSH
- sekvence aminokyselin MeSH
- sekvenční seřazení MeSH
- signální transdukce MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
PCB 136 is an environmentally relevant chiral PCB congener, which has been found in vivo to be present in form of rotational isomers (atropisomers). Its atropselective biotransformation or neurotoxic effects linked with sensitization of ryanodine receptor suggest that it might interact also with other intracellular receptors in a stereospecific manner. However, possible atropselective effects of PCB 136 on nuclear receptor transactivation remain unknown. Therefore, in this study, atropselective effects of PCB 136 on nuclear receptors controlling endocrine signaling and/or expression of xenobiotic and steroid hormone catabolism were investigated. PCB136 atropisomers were found to exert differential effects on estrogen receptor (ER) activation; (+)-PCB 136 was estrogenic, while (-)-PCB 136 was antiestrogenic. In contrast, inhibition of androgen receptor (AR) activity was not stereospecific. Both PCB136 stereoisomers induced the constitutive androgen receptor (CAR)-dependent gene expression; however, no significant stereospecificity of PCB 136 atropisomers was observed. PCB136 was a partial inducer of the pregnane X receptor (PXR)-dependent gene expression. Here, (-)-PCB 136 was a significantly more potent inducer of PXR activity than (+)-PCB 136. Taken together, the present results indicate that at least two nuclear receptors participating in endocrine regulation or metabolism, ER and PXR, could be regulated in an atropselective manner by chiral PCB 136. The enantioselective enrichment of PCB atropisomers in animal and human tissues may thus have significant consequences for endocrine-disrupting effects of chiral ortho-substituted PCB congeners.
The Pregnane X (PXR), Vitamin D (VDR) and Farnesoid X (FXR) nuclear receptors have been shown to be receptors of bile acids controlling their detoxification or synthesis. Chenodeoxycholic (CDCA) and lithocholic (LCA) acids are ligands of FXR and VDR, respectively, whereas 3-keto and acetylated derivates of LCA have been described as ligands for all three receptors. In this study, we hypothesized that oxidation or acetylation at position 3, 7 and 12 of bile acids DCA (deoxycholic acid), LCA, CA (cholic acid), and CDCA by detoxification enzymes or microbiome may have an effect on the interactions with bile acid nuclear receptors. We employed reporter gene assays in HepG2 cells, the TR-FRET assay with recombinant PXR and RT-PCR to study the effects of acetylated and keto bile acids on the nuclear receptors activation and their target gene expression in differentiated hepatic HepaRG cells. We demonstrate that the DCA 3,12-diacetate and CA 3,7,12-triacetate derivatives are ligands of PXR and DCA 3,12-diacetate induces PXR target genes such as CYP3A4, CYP2B6 and ABCB1/MDR1. In conclusion, we found that acetylated DCA and CA are potent ligands of PXR. Whether the acetylated bile acid derivatives are novel endogenous ligands of PXR with detoxification or physiological functions should be further studied in ongoing experiments.
- MeSH
- acetylace MeSH
- buněčné kultury MeSH
- buňky Hep G2 MeSH
- cytochrom P-450 CYP3A genetika MeSH
- cytochrom P450 CYP2B6 genetika MeSH
- hepatocyty účinky léků enzymologie metabolismus MeSH
- kyselina cholová chemie metabolismus farmakologie MeSH
- kyselina deoxycholová chemie metabolismus farmakologie MeSH
- lidé MeSH
- ligandy MeSH
- myši MeSH
- oxidace-redukce MeSH
- P-glykoprotein genetika MeSH
- plazmidy MeSH
- receptory cytoplazmatické a nukleární chemie genetika metabolismus MeSH
- receptory kalcitriolu chemie genetika metabolismus MeSH
- reportérové geny MeSH
- simulace molekulového dockingu MeSH
- steroidní receptory chemie genetika metabolismus MeSH
- techniky dvojhybridového systému MeSH
- transfekce MeSH
- vazba proteinů MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Genome predictions based on selected genes would be a very welcome approach for taxonomic studies. We analyzed three genes, recN, flaA, and ftsY, for determining if these genes are useful tools for systematic analyses in the genus Anoxybacillus. The genes encoding a DNA repair and genetic recombination protein (recN), the flagellin protein (flaA), and GTPase signal docking protein (ftsY) were sequenced for ten Anoxybacillus species. The sequence comparisons revealed that recN sequence similarities range between 61% and 99% in the genus Anoxybacillus. Comparisons to other bacterial recN genes indicated that levels of similarity did not differ from the levels within genus Anoxybacillus. These data showed that recN is not a useful marker for the genus Anoxybacillus. A 550-600-bp region of the flagellin gene was amplified for all Anoxybacillus strains except for Anoxybacillus contaminans. The sequence similarity of flaA gene varies between 61% and 76%. Comparisons to other bacterial flagellin genes obtained from GenBank (Bacillus, Pectinatus, Proteus, and Vibrio) indicated that the levels of similarity were lower (3-42%). Based on these data, we concluded that the variability in this single gene makes it a particularly useful marker. Another housekeeping gene ftsY suggested to reflect the G+C (mol/mol) content of whole genome was analyzed for Anoxybacillus strains. A mean difference of 1.4% was observed between the G+C content of the gene ftsY and the G+C content of the whole genome. These results showed that the gene ftsY can be used to represent whole G+C content of the Anoxybacillus species.
- MeSH
- Anoxybacillus chemie klasifikace genetika izolace a purifikace MeSH
- bakteriální proteiny chemie genetika MeSH
- flagelin chemie genetika MeSH
- fylogeneze MeSH
- molekulární sekvence - údaje MeSH
- receptory cytoplazmatické a nukleární chemie genetika MeSH
- restrikční enzymy chemie genetika MeSH
- sekvence nukleotidů MeSH
- sekvenční homologie nukleových kyselin MeSH
- zastoupení bazí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nuclear receptors (NRs), or nuclear hormone receptors (NHRs), are transcription factors that regulate development and metabolism of most if not all animal species. Their regulatory networks include conserved mechanisms that are shared in-between species as well as mechanisms that are restricted to certain phyla or even species. In search for conserved members of the NHR family in Schmidtea mediterranea, we identified a molecular signature of a class of NRs, NR2E1, in the S. mediterranea genome and cloned its complete cDNA coding sequence. The derived amino acid sequence shows a high degree of conservation of both DNA-binding domain and ligand- binding domain and a remarkably high homology to vertebrate NR2E1 and C. elegans NHR-67. Quantitative PCR detected approximately ten-fold higher expression of Smed-tlx-1 in the proximal part of the head compared to the tail region. The expression of Smed-tlx-1 is higher during fed state than during fasting. Smed-tlx-1 down-regulation by RNA interference affects the ability of the animals to maintain body plan and induces defects of brain, eyes and body shape during fasting and re-growing cycles. These results suggest that SMED-TLX-1 is critical for tissue and body plan maintenance in planaria.
- MeSH
- fylogeneze MeSH
- klonování DNA MeSH
- lidé MeSH
- molekulární sekvence - údaje MeSH
- omezení příjmu potravy fyziologie MeSH
- orgánová specificita genetika MeSH
- proteiny červů genetika chemie metabolismus MeSH
- receptory cytoplazmatické a nukleární genetika chemie metabolismus MeSH
- regulace genové exprese MeSH
- RNA interference MeSH
- rozvržení tělního plánu genetika MeSH
- sekvence aminokyselin MeSH
- sekvenční seřazení MeSH
- stravovací zvyklosti fyziologie MeSH
- Turbellaria embryologie fyziologie genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
- MeSH
- arterioskleróza farmakoterapie imunologie metabolismus MeSH
- finanční podpora výzkumu jako téma MeSH
- glukosa metabolismus MeSH
- inzulinová rezistence MeSH
- lipidy genetika MeSH
- metabolismus lipidů MeSH
- proliferátory peroxizomů agonisté MeSH
- receptory cytoplazmatické a nukleární genetika chemie klasifikace MeSH
- Publikační typ
- přehledy MeSH
