Cellular RNA polymerase is a multi-subunit macromolecular assembly responsible for gene transcription, a highly regulated process conserved from bacteria to humans. In bacteria, sigma factors are employed to mediate gene-specific expression in response to a variety of environmental conditions. The major variant σ factor, σ, has a specific role in stress responses. Unlike σ-dependent transcription, which often can spontaneously proceed to initiation, σ-dependent transcription requires an additional ATPase protein for activation. As a result, structures of a number of distinct functional states during the dynamic process of transcription initiation have been captured using the σ system with both x-ray crystallography and cryo electron microscopy, furthering our understanding of σ-dependent transcription initiation and DNA opening. Comparisons with σ and eukaryotic polymerases reveal unique and common features during transcription initiation.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7057263 | PMC |
http://dx.doi.org/10.1016/j.jmb.2019.04.022 | DOI Listing |
Cell Mol Gastroenterol Hepatol
March 2022
Institute of Biochemistry, Food Science and Nutrition. Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem, Rehovot, Israel. Electronic address:
Background & Aims: Gluconeogenesis from amino acids (AAs) maintains glucose homeostasis during fasting. Although glucagon is known to regulate AA catabolism, the contribution of other hormones to it and the scope of transcriptional regulation dictating AA catabolism are unknown. We explored the role of the fasting hormones glucagon and glucocorticoids in transcriptional regulation of AA catabolism genes and AA-dependent gluconeogenesis.
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
August 2019
Department of Urology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
Corticotropin-releasing factor (CRF) regulates stress responses, and aberrant CRF signals are associated with depressive disorders. expression is responsive to arachidonic acid (AA), where CRF is released from the hypothalamic paraventricular nucleus (PVN) to initiate the hypothalamic-pituitary-adrenal axis, culminating in glucocorticoid stress hormone release. Despite this biological and clinical significance, regulation is unclear.
View Article and Find Full Text PDFChannels (Austin)
December 2019
a Department of Molecular Cell Physiology, Institute of Cell Biophysics, Russian Academy of Sciences , Pushchino , Moscow Region , Russia.
The current knowledge of electrogenesis in mesenchymal stromal cells (MSCs) remains scarce. Earlier, we demonstrated that in MSCs from the human adipose tissue, transduction of certain agonists involved the phosphoinositide cascade. Its pivotal effector PLC generates DAG that can regulate ion channels directly or via its derivatives, including arachidonic acid (AA).
View Article and Find Full Text PDFBiomed Pharmacother
February 2017
Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, One John Marshall Drive, Huntington, WV 25755, United States. Electronic address:
Introduction: Accumulation of hypoxia inducible factor-1 alpha (HIF-1α) in malignant tissue is known to contribute to oncogenic progression and is inversely associated with patient survival. Ascorbic acid (AA) depletion in malignant tissue may contribute to aberrant normoxic activity of HIF-1α. While AA supplementation has been shown to attenuate HIF-1α function in malignant melanoma, the use of dehydroascorbic acid (DHA) as a therapeutic means to increase intracellular AA and modulate HIF-1α function is yet to be evaluated.
View Article and Find Full Text PDFNat Commun
February 2015
1] Wisconsin Institute for Discovery, University of Wisconsin, Madison, 330 N. Orchard Street, Room 2118, Wisconsin 53715, USA [2] Department of Cell and Regenerative Biology, University of Wisconsin, Madison, 330 N. Orchard Street, Room 2118, Wisconsin 53715, USA.
Reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) represents a profound change in cell fate. Here, we show that combining ascorbic acid (AA) and 2i (MAP kinase and GSK inhibitors) increases the efficiency of reprogramming from fibroblasts and synergistically enhances conversion of partially reprogrammed intermediates to the iPSC state. AA and 2i induce differential transcriptional responses, each leading to the activation of specific pluripotency loci.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!