Among the set of Argonautes proteins encoded by metazoan genomes, some have conserved amino acids important for catalytic or slicing activity. The functional significance of these residues in microRNA (miRNA)-specific Argonautes in animals is still unclear since miRNAs do not induce site-specific cleavage of targeted messenger RNAs (mRNAs), unlike small interfering RNAs (siRNAs). Here, we report that miRNA-specific ALG-1 and ALG-2 Argonautes from Caenorhabditis elegans possess the slicing activity normally implicated in the siRNA-silencing pathway. We also find that ALG-1/2 can bind and use a Dicer-processed miRNA duplex to target mRNAs, suggesting an ability to displace RNA strands. Importantly, the slicing activity of ALG-1 or ALG-2 is essential for the miRNA pathway in vivo, as shown by the accumulation of truncated miRNA precursors and altered miRNA-induced silencing complex (miRISC) formation. Taken together, our data demonstrate that the slicing activity of Argonautes contributes to a new and unexpected step in the canonical miRNA pathway that occurs prior to miRISC loading in animals.
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http://dx.doi.org/10.1093/nar/gks748 | DOI Listing |
NPJ Regen Med
January 2025
Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA.
Cardiomyocytes (CMs) lost during ischemic cardiac injury cannot be replaced due to their limited proliferative capacity. Calcium is an important signal transducer that regulates key cellular processes, but its role in regulating CM proliferation is incompletely understood. Here we show a robust pathway for new calcium signaling-based cardiac regenerative strategies.
View Article and Find Full Text PDFNeuropeptides
January 2025
Department of Pathophysiology, Faculty of Medicine, University of Szeged, Hungary.
Corticotropin-releasing factor (CRF) and urocortins (UCN1, UCN2 and UCN3) belong to the same CRF family of neuropeptides. They regulate the neuroendocrine, autonomic and behavioral responses to stress via two CRF receptors (CRF1 and CRF2). Stress, anxiety and depression affects the activity of the hypothalamic-pituitary-adrenal (HPA) axis and the serotoninergic neurotransmission, both being regulated by CRF and CRF-related peptides.
View Article and Find Full Text PDFACS Chem Neurosci
January 2025
Departments of Psychiatry and Neurology, Division of Molecular Therapeutics, New York State Psychiatric Institute, Columbia University Medical Center, New York, New York 10032, United States.
Voluntary movement, motivation, and reinforcement learning depend on the activity of ventral midbrain neurons, which extend axons to release dopamine (DA) in the striatum. These neurons exhibit two patterns of action potential activity: low-frequency tonic activity that is intrinsically generated and superimposed high-frequency phasic bursts that are driven by synaptic inputs. acute striatal brain preparations are widely employed to study the regulation of evoked DA release but exhibit very different DA release kinetics than recordings.
View Article and Find Full Text PDFBioorg Med Chem Lett
January 2025
Department of Chemistry, Simon Fraser University Burnaby British Columbia Canada. Electronic address:
Prostaglandin E receptor type 4 (EP4) agonists have been shown to be effective in treating experimental ulcerative colitis (UC) in animals and in human clinical trials, but their development has been impeded by unacceptable systemic side effects. In this study, a series of methylene phosphate prodrugs of a highly potent and selective prostaglandin EP4 receptor agonist were designed to target and remain localized in the gastrointestinal (GI) tract after either oral or rectal instillation. The prodrugs were designed to be converted to liberate active EP4 agonist by intestinal alkaline phosphate (IAP), a ubiquitous enzyme found at the luminal of the intestinal wall thus exposing the colon epithelial barrier while reducing systemic exposure to the active agonist.
View Article and Find Full Text PDFIndian J Nucl Med
November 2024
Department of Nuclear Medicine and Molecular Imaging, Homi Bhabha Cancer Hospital & Mahamana Pandit Madan Mohan Malaviya Cancer Centre, Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Varanasi, India.
Background: The introduction of positron emission tomography/computed tomography (PET/CT) has significantly advanced medical imaging. In oncology, F-fluorodeoxyglucose (F-FDG) PET/CT is particularly crucial for staging, evaluating treatment response, monitoring follow-up, and planning radiotherapy. However, in resource limiting hospitals, the availability of fluorine-labeled F-FDG limits optimal scan acquisition.
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