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The cellular adaptive response to hypoxia, mediated by high HIF1α levels includes metabolic reprogramming, restricted DNA replication and cell division. In contrast to healthy cells, the genome of cancer cells, and Kaposi's sarcoma associated herpesvirus (KSHV) infected cells maintains replication in hypoxia. We show that KSHV infection, despite promoting expression of HIF1α in normoxia, can also restrict transcriptional activity, and promoted its degradation in hypoxia. KSHV-encoded vCyclin, expressed in hypoxia, mediated HIF1α cytosolic translocation, and its degradation through a non-canonical lysosomal pathway. Attenuation of HIF1α levels by vCyclin allowed cells to bypass the block to DNA replication and cell proliferation in hypoxia. These results demonstrated that KSHV utilizes a unique strategy to balance HIF1α levels to overcome replication arrest and induction of the oncogenic phenotype, which are dependent on the levels of oxygen in the microenvironment.
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http://dx.doi.org/10.7554/eLife.57436 | DOI Listing |
Environ Pollut
June 2024
Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life, Earth & Environment, University of Namur, Rue de Bruxelles, 61-B-5000, Namur, Belgium.
The chorion is the first protective barrier set to prevent numerous pollutants from damaging the developing embryo. However, depending on their size, some nanoplastics (NPs) can pass through this barrier and reach the embryo, while all microplastics (MPs) remain on the outside. This study brings a straight approach to compare MPs and NPs, and assess their direct and indirect effects on zebrafish embryos and larvae.
View Article and Find Full Text PDFJ Comp Physiol B
July 2021
Department of Biology, University of Ottawa, Gendron Hall, 30 Marie Curie Private, Ottawa, ON, K1N 6N5, Canada.
Previous studies have demonstrated that hypoxia tolerance is improved in zebrafish (Danio rerio) larvae after prior exposure to lowered ambient O levels. Such improved hypoxia performance was attributed in part, to increased levels of hypoxia-inducible factor 1α (Hif-1α) exerting downstream effects on various physiological processes including promotion of trunk skin angiogenesis. Since O uptake ([Formula: see text]) in larvae is facilitated largely by O diffusion across the skin, enhanced cutaneous vascularization is expected to enhance [Formula: see text] during hypoxia and thus contribute to improved hypoxia tolerance.
View Article and Find Full Text PDFSci Rep
October 2020
College of Fisheries, National Demonstration Center for Experimental Aquaculture Education, Huazhong Agricultural University, Wuhan, 430070, China.
Hypoxia-inducible factor 1 (HIF-1) functions as a master regulator of the cellular response to hypoxic stress. Two HIF-1α paralogs, HIF-1αA and HIF-1αB, were generated in euteleosts by the specific, third round of genome duplication, but one paralog was later lost in most families with the exception of cyprinid fish. How these duplicates function in mitochondrial regulation and whether their preservation contributes to the hypoxia tolerance demonstrated by cyprinid fish in freshwater environments is not clear.
View Article and Find Full Text PDFJ Immunol
January 2019
The Bateson Centre, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom;
Drug-resistant mycobacteria are a rising problem worldwide. There is an urgent need to understand the immune response to tuberculosis to identify host targets that, if targeted therapeutically, could be used to tackle these currently untreatable infections. In this study we use an Il-1β fluorescent transgenic line to show that there is an early innate immune proinflammatory response to well-established zebrafish models of inflammation and infection.
View Article and Find Full Text PDFJ Exp Biol
December 2016
Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5.
The present study investigated the potential role of hypoxia-inducible factor (HIF) in calcium homeostasis in developing zebrafish (Danio rerio). It was demonstrated that zebrafish raised in hypoxic water (30 mmHg; control, 155 mmHg P ) until 4 days post-fertilization exhibited a substantial reduction in whole-body Ca levels and Ca uptake. Ca uptake in hypoxia-treated fish did not return to pre-hypoxia (control) levels within 2 h of transfer back to normoxic water.
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