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Vidaurre V, Song A, Li T, Ku WL, Zhao K, Qian J, Chen X. The Drosophila histone methyl-transferase SET1 coordinates multiple signaling pathways in regulating male germline stem cell maintenance and differentiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580277. [PMID: 38405894 PMCID: PMC10888844 DOI: 10.1101/2024.02.14.580277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Many cell types come from tissue-specific adult stem cells that maintain the balance between proliferation and differentiation. Here, we study how the H3K4me3 methyltransferase, Set1, regulates early-stage male germ cell proliferation and differentiation in Drosophila. Early-stage germline-specific knockdown of set1 results in a temporally progressed defects, arising as germ cell loss and developing to overpopulated early-stage germ cells. These germline defects also impact the niche architecture and cyst stem cell lineage in a non-cell-autonomous manner. Additionally, wild-type Set1, but not the catalytically inactive Set1, could rescue the set1 knockdown phenotypes, highlighting the functional importance of the methyl-transferase activity of the Set1 enzyme. Further, RNA-seq experiments reveal key signaling pathway components, such as the JAK-STAT pathway gene stat92E and the BMP pathway gene mad, that are upregulated upon set1 knockdown. Genetic interaction assays support the functional relationships between set1 and JAK-STAT or BMP pathways, as mutations of both the stat92E and mad genes suppress the set1 knockdown phenotypes. These findings enhance our understanding of the balance between proliferation and differentiation in an adult stem cell lineage. The germ cell loss followed by over-proliferation phenotypes when inhibiting a histone methyl-transferase raise concerns about using their inhibitors in cancer therapy.
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Affiliation(s)
- Velinda Vidaurre
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Annabelle Song
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Taibo Li
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Wai Lim Ku
- Systems Biology Center, National Heart, Lung and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Keji Zhao
- Systems Biology Center, National Heart, Lung and Blood Institute, NIH, Bethesda, Maryland, United States of America
| | - Jiang Qian
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Xin Chen
- Howard Hughes Medical Institute, Baltimore, Maryland, United States of America
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland, United States of America
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Mi T, Mack JO, Koolmees W, Lyon Q, Yochimowitz L, Teng ZQ, Jiang P, Montell C, Zhang YV. Alkaline taste sensation through the alkaliphile chloride channel in Drosophila. Nat Metab 2023; 5:466-480. [PMID: 36941450 PMCID: PMC10665042 DOI: 10.1038/s42255-023-00765-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 02/09/2023] [Indexed: 03/23/2023]
Abstract
The sense of taste is an important sentinel governing what should or should not be ingested by an animal, with high pH sensation playing a critical role in food selection. Here we explore the molecular identities of taste receptors detecting the basic pH of food using Drosophila melanogaster as a model. We identify a chloride channel named alkaliphile (Alka), which is both necessary and sufficient for aversive taste responses to basic food. Alka forms a high-pH-gated chloride channel and is specifically expressed in a subset of gustatory receptor neurons (GRNs). Optogenetic activation of alka-expressing GRNs is sufficient to suppress attractive feeding responses to sucrose. Conversely, inactivation of these GRNs causes severe impairments in the aversion to high pH. Altogether, our discovery of Alka as an alkaline taste receptor lays the groundwork for future research on alkaline taste sensation in other animals.
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Affiliation(s)
- Tingwei Mi
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | - John O Mack
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | | | - Quinn Lyon
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | | | - Zhao-Qian Teng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
| | - Peihua Jiang
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | - Craig Montell
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Yali V Zhang
- Monell Chemical Senses Center, Philadelphia, PA, USA.
- Department of Physiology, The Diabetes Research Center, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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Tadres D, Wong PH, To T, Moehlis J, Louis M. Depolarization block in olfactory sensory neurons expands the dimensionality of odor encoding. SCIENCE ADVANCES 2022; 8:eade7209. [PMID: 36525486 PMCID: PMC9757753 DOI: 10.1126/sciadv.ade7209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/15/2022] [Indexed: 05/20/2023]
Abstract
Upon strong and prolonged excitation, neurons can undergo a silent state called depolarization block that is often associated with disorders such as epileptic seizures. Here, we show that neurons in the peripheral olfactory system undergo depolarization block as part of their normal physiological function. Typically, olfactory sensory neurons enter depolarization block at odor concentrations three orders of magnitude above their detection threshold, thereby defining receptive fields over concentration bands. The silencing of high-affinity olfactory sensory neurons produces sparser peripheral odor representations at high-odor concentrations, which might facilitate perceptual discrimination. Using a conductance-based model of the olfactory transduction cascade paired with spike generation, we provide numerical and experimental evidence that depolarization block arises from the slow inactivation of sodium channels-a process that could affect a variety of sensory neurons. The existence of ethologically relevant depolarization block in olfactory sensory neurons creates an additional dimension that expands the peripheral encoding of odors.
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Affiliation(s)
- David Tadres
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, USA
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Philip H. Wong
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, USA
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Thuc To
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Jeff Moehlis
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Matthieu Louis
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, USA
- Department of Physics, University of California, Santa Barbara, Santa Barbara, CA, USA
- Corresponding author.
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Abstract
Precise genetic manipulation of specific cell types or tissues to pinpoint gene function requirement is a critical step in studies aimed at unraveling the intricacies of organismal physiology. Drosophila researchers heavily rely on the UAS/Gal4/Gal80 system for tissue-specific manipulations; however, it is often unclear whether the reported Gal4 expression patterns are indeed specific to the tissue of interest such that experimental results are not confounded by secondary sites of Gal4 expression. Here, we surveyed the expression patterns of commonly used Gal4 drivers in adult Drosophila female tissues under optimal conditions and found that multiple drivers have unreported secondary sites of expression beyond their published cell type/tissue expression pattern. These results underscore the importance of thoroughly characterizing Gal4 tools as part of a rigorous experimental design that avoids potential misinterpretation of results as we strive for understanding how the function of a specific gene/pathway in one tissue contributes to whole-body physiology.
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