Browsing by Subject "Transcription factor"

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  • Nikparvar, Bahareh; Andreevskaya, Margarita; Duru, Ilhan C.; Bucur, Florentina I.; Grigore-Gurgu, Leontina; Borda, Daniela; Nicolau, Anca I.; Riedel, Christian U.; Auvinen, Petri; Bar, Nadav (2021)
    Background The pathogen Listeria (L.) monocytogenes is known to survive heat, cold, high pressure, and other extreme conditions. Although the response of this pathogen to pH, osmotic, temperature, and oxidative stress has been studied extensively, its reaction to the stress produced by high pressure processing HPP (which is a preservation method in the food industry), and the activated gene regulatory network (GRN) in response to this stress is still largely unknown. Results We used RNA sequencing transcriptome data of L. monocytogenes (ScottA) treated at 400 MPa and 8(circle)C, for 8 min and combined it with current information in the literature to create a transcriptional regulation database, depicting the relationship between transcription factors (TFs) and their target genes (TGs) in L. monocytogenes. We then applied network component analysis (NCA), a matrix decomposition method, to reconstruct the activities of the TFs over time. According to our findings, L. monocytogenes responded to the stress applied during HPP by three statistically different gene regulation modes: survival mode during the first 10 min post-treatment, repair mode during 1 h post-treatment, and re-growth mode beyond 6 h after HPP. We identified the TFs and their TGs that were responsible for each of the modes. We developed a plausible model that could explain the regulatory mechanism that L. monocytogenes activated through the well-studied CIRCE operon via the regulator HrcA during the survival mode. Conclusions Our findings suggest that the timely activation of TFs associated with an immediate stress response, followed by the expression of genes for repair purposes, and then re-growth and metabolism, could be a strategy of L. monocytogenes to survive and recover extreme HPP conditions. We believe that our results give a better understanding of L. monocytogenes behavior after exposure to high pressure that may lead to the design of a specific knock-out process to target the genes or mechanisms. The results can help the food industry select appropriate HPP conditions to prevent L. monocytogenes recovery during food storage.
  • Nikparvar, Bahareh; Andreevskaya, Margarita; Duru, Ilhan C; Bucur, Florentina I; Grigore-Gurgu, Leontina; Borda, Daniela; Nicolau, Anca I; Riedel, Christian U; Auvinen, Petri; Bar, Nadav (BioMed Central, 2021)
    Abstract Background The pathogen Listeria (L.) monocytogenes is known to survive heat, cold, high pressure, and other extreme conditions. Although the response of this pathogen to pH, osmotic, temperature, and oxidative stress has been studied extensively, its reaction to the stress produced by high pressure processing HPP (which is a preservation method in the food industry), and the activated gene regulatory network (GRN) in response to this stress is still largely unknown. Results We used RNA sequencing transcriptome data of L. monocytogenes (ScottA) treated at 400 MPa and 8∘C, for 8 min and combined it with current information in the literature to create a transcriptional regulation database, depicting the relationship between transcription factors (TFs) and their target genes (TGs) in L. monocytogenes. We then applied network component analysis (NCA), a matrix decomposition method, to reconstruct the activities of the TFs over time. According to our findings, L. monocytogenes responded to the stress applied during HPP by three statistically different gene regulation modes: survival mode during the first 10 min post-treatment, repair mode during 1 h post-treatment, and re-growth mode beyond 6 h after HPP. We identified the TFs and their TGs that were responsible for each of the modes. We developed a plausible model that could explain the regulatory mechanism that L. monocytogenes activated through the well-studied CIRCE operon via the regulator HrcA during the survival mode. Conclusions Our findings suggest that the timely activation of TFs associated with an immediate stress response, followed by the expression of genes for repair purposes, and then re-growth and metabolism, could be a strategy of L. monocytogenes to survive and recover extreme HPP conditions. We believe that our results give a better understanding of L. monocytogenes behavior after exposure to high pressure that may lead to the design of a specific knock-out process to target the genes or mechanisms. The results can help the food industry select appropriate HPP conditions to prevent L. monocytogenes recovery during food storage.
  • Das, Bishwajit (Helsingin yliopisto, 2020)
    Asteraceae comprises of approximately 10% of all angiosperm plant species. These species are well known for their highly compressed inflorescences known as capitula which consists of morphologically different types of flowers: ray, trans and disc flowers. This immense morphological difference excels Gerbera as an ideal plant to study flower type differentiations. Even though this complex process is governed by several genes, the ray flower identity is believed to be greatly influenced by GhCYC3 promoter mediated gene regulations. In previous studies two TCP transcription factors (TF): GhCIN1and GhCIN2, and two MADS TFs: GAGA1 and RCD5 were identified as the potential upstream regulators of GhCYC3. So, the aim of this study is to test whether these potential upstream regulators physically bind to GhCYC3 promoter in in vitro conditions. In order to achieve the goal, these transcription factor proteins from Gerbera hybrida were successfully expressed in E. coli and purified as fusion proteins to maltose-binding protein (MBP). Physical binding of the purified fusion proteins to the putative target DNA sites in the promoter region of GhCYC3 gene was tested by electrophoretic mobility shift assay (EMSA). The results showed that none of the gerbera transcription factors (GhCIN1, GhCIN2, GAGA1 and RCD5) bind to their putative target sites under the condition tested in this study. However, it might not be justifiable to deduce that these TFs do not interact with GhCYC3 promoter. The absence of in vitro interaction between the tested TFs and GhCYC3 promoter might be caused by either lack of proper folding and activity of the TFs or absence of co-factors which are available in vivo.
  • Mattila, Hans K; Mäkinen, Mari; Lundell, Taina (BioMed Central, 2020)
    Abstract Background Fungal decomposition of wood is considered as a strictly aerobic process. However, recent findings on wood-decaying fungi to produce ethanol from various lignocelluloses under oxygen-depleted conditions lead us to question this. We designed gene expression study of the white rot fungus Phlebia radiata (isolate FBCC0043) by adopting comparative transcriptomics and functional genomics on solid lignocellulose substrates under varying cultivation atmospheric conditions. Results Switch to fermentative conditions was a major regulator for intracellular metabolism and extracellular enzymatic degradation of wood polysaccharides. Changes in the expression profiles of CAZy (carbohydrate-active enzyme) encoding genes upon oxygen depletion, lead into an alternative wood decomposition strategy. Surprisingly, we noticed higher cellulolytic activity under fermentative conditions in comparison to aerobic cultivation. In addition, our results manifest how oxygen depletion affects over 200 genes of fungal primary metabolism including several transcription factors. We present new functions for acetate generating phosphoketolase pathway and its potential regulator, Adr1 transcription factor, in carbon catabolism under oxygen depletion. Conclusions Physiologically resilient wood-decomposing Basidiomycota species P. radiata is capable of thriving under respirative and fermentative conditions utilizing only untreated lignocellulose as carbon source. Hypoxia-response mechanism in the fungus is, however, divergent from the regulation described for Ascomycota fermenting yeasts or animal-pathogenic species of Basidiomycota.
  • Acosta, Alicia Jurado; Rysä, Jaana; Szabo, Zoltan; Moilanen, Anne-Mari; Komati, Hiba; Nemer, Mona; Ruskoaho, Heikki (2017)
    The phenylephrine-induced complex-1 (PEX1) transcription factor, also known as zinc-finger protein 260 (Zfp260), is an effector of endothelin-1 and alpha(1)-adrenergic signaling in cardiac hypertrophy. However, the role of PEX1 in transcriptional regulation of myocardial remodeling remains largely unknown. In the present study, we used PEX1 gain- and loss-of-function to examine the effects of PEX1 on left ventricular remodeling. Adenoviral constructs expressing PEX1, antisense PEX1, or LacZ were delivered by local injection into the anterior wall of the left ventricle in Sprague-Dawley rats. PEX1 overexpression led to induction of hypertrophic gene program and increased fibrosis. In agreement with this, the expression of genes involved in the fibrotic process, such as collagens I and III, matrix metalloproteinases (MMPs), fibronectin-1, transforming growth factor beta-1 and connective tissue growth factor, were significantly up-regulated following PEX1 overexpression, whereas silencing of PEX1 significantly inhibited the expression of pro-fibrotic genes and increased left ventricular ejection fraction and fractional shortening. In vitro luciferase reporter assays showed that PEX1 regulates the expression of MMP-9 by activating promoter. Furthermore, PEX1 gain- and loss-of-function experiments in rat neonatal cardiac fibroblasts and myocytes revealed that MMP-9 gene expression was affected by PEX1 predominantly in fibroblasts. Our results indicate that PEX1 is involved in regulating cardiac fibrosis and extracellular matrix turnover, particularly fibroblasts being responsible for the fibrosis-associated changes in gene expression. Furthermore, PEX1 activation of the MMP-9 promoter triggers the pro-fibrotic response directed by PEX1.