The Wnt signaling pathway controls stem cell identity in the intestinal epithelium and in many other adult organs. The transcription factor Ascl2 (a Wnt target gene) is a master regulator of intestinal stem cell identity. It is unclear how the continuous Wnt gradient along the crypt axis is translated into discrete expression of Ascl2 and discrete specification of stem cells at crypt bottoms. We show that (1) Ascl2 is regulated in a direct autoactivatory loop, leading to a distinct on/off expression pattern, and (2) Wnt/R-spondin can activate this regulatory loop. This mechanism interprets the Wnt levels in the intestinal crypt and translates the continuous Wnt signal into a discrete Ascl2 "on" or "off" decision. In turn, Ascl2, together with β-catenin/Tcf, activates the genes fundamental to the stem cell state. In this manner, Ascl2 forms a transcriptional switch that is both Wnt responsive and Wnt dependent to define stem cell identity.
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http://dx.doi.org/10.1016/j.stem.2014.12.006 | DOI Listing |
Clin Infect Dis
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Department of Cellular Therapy and Allogeneic Stem Cell Transplantation, Karolinska University Hospital Huddinge, Karolinska Comprehensive Cancer Center, Stockholm, Sweden.
Herpes simplex virus (HSV) infection is one of the most prevalent viral infections worldwide. In general, host immunity is sufficient to clear viral shedding and recurrences, although it is insufficient to prevent subsequent virologic reactivations. In immunocompromised patients, prolonged and difficult-to-treat HSV infections may develop.
View Article and Find Full Text PDFAlzheimers Dement
January 2025
Department of Neuroscience, City University of Hong Kong, Hong Kong, Hong Kong.
Introduction: Antisense oligonucleotides (ASOs) have shown promise in reducing amyloid precursor protein (APP) levels in neurons, but their effects in astrocytes, key contributors to neurodegenerative diseases, remain unclear. This study evaluates the efficacy of APP ASOs in astrocytes derived from an individual with Down syndrome (DS), a population at high risk for Alzheimer's disease (AD).
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Int J Phytoremediation
January 2025
Graduate School of Environmental Studies, Tohoku University, Sendai, Japan.
ssp. is well known as a Cd hyperaccumulator. Yet, understanding how this plant survives in a high Cd environment without appearing toxicity signs is far from complete.
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Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, 1161 21st Ave S, Nashville, Tennessee, 37232, United States of America.
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