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Bertrand JU, Petit V, Aktary Z, de la Grange P, Elkoshi N, Sohier P, Delmas V, Levy C, Larue L. Loss of Dicer in Newborn Melanocytes Leads to Premature Hair Graying and Changes in Integrin Expression. J Invest Dermatol 2024; 144:601-611. [PMID: 37739336 DOI: 10.1016/j.jid.2023.08.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/24/2023]
Abstract
Premature hair graying occurs owing to the depletion of melanocyte stem cells in the hair follicle, which can be accelerated by stress caused by genetic or environmental factors. However, the connection between stress and melanocyte stem cell loss is not fully understood. MicroRNAs are molecules that control gene expression by regulating mRNA stability and translation and are produced by the enzyme Dicer, which is repressed under stress. In this study, using 2 mouse genetic models and human and mouse cell lines, we found that the inactivation of Dicer in melanocytes leads to misplacement of these cells within the hair follicle, resulting in a lack of melanin transfer to keratinocytes in the growing hair and the exhaustion of the melanocyte stem cell pool. We also show that miR-92b, which regulates ItgaV mRNA and protein levels, plays a role in altering melanocyte migration. Overall, our findings suggest that the Dicer-miR92b-ItgaV pathway serves as a major signaling pathway linking stress to premature hair greying.
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Affiliation(s)
- Juliette U Bertrand
- INSERM U1021, Normal and Pathological Development of Melanocytes, Institut Curie, PSL Research University, Orsay, France; Centre National de la Recherche Scientifique (CNRS) UMR 3347, Univ Paris-Sud, Univ Paris-Saclay, Orsay, France
| | - Valérie Petit
- INSERM U1021, Normal and Pathological Development of Melanocytes, Institut Curie, PSL Research University, Orsay, France; Centre National de la Recherche Scientifique (CNRS) UMR 3347, Univ Paris-Sud, Univ Paris-Saclay, Orsay, France
| | - Zackie Aktary
- INSERM U1021, Normal and Pathological Development of Melanocytes, Institut Curie, PSL Research University, Orsay, France; Centre National de la Recherche Scientifique (CNRS) UMR 3347, Univ Paris-Sud, Univ Paris-Saclay, Orsay, France
| | | | - Nadav Elkoshi
- Department of Human Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel-Aviv, Israel
| | - Pierre Sohier
- INSERM U1021, Normal and Pathological Development of Melanocytes, Institut Curie, PSL Research University, Orsay, France; Centre National de la Recherche Scientifique (CNRS) UMR 3347, Univ Paris-Sud, Univ Paris-Saclay, Orsay, France
| | - Véronique Delmas
- INSERM U1021, Normal and Pathological Development of Melanocytes, Institut Curie, PSL Research University, Orsay, France; Centre National de la Recherche Scientifique (CNRS) UMR 3347, Univ Paris-Sud, Univ Paris-Saclay, Orsay, France
| | - Carmit Levy
- Department of Human Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel-Aviv, Israel
| | - Lionel Larue
- INSERM U1021, Normal and Pathological Development of Melanocytes, Institut Curie, PSL Research University, Orsay, France; Centre National de la Recherche Scientifique (CNRS) UMR 3347, Univ Paris-Sud, Univ Paris-Saclay, Orsay, France.
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Dadhwal G, Samy H, Bouvette J, El-Azzouzi F, Dagenais P, Legault P. Substrate promiscuity of Dicer toward precursors of the let-7 family and their 3'-end modifications. Cell Mol Life Sci 2024; 81:53. [PMID: 38261114 PMCID: PMC10806991 DOI: 10.1007/s00018-023-05090-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 11/27/2023] [Accepted: 12/12/2023] [Indexed: 01/24/2024]
Abstract
The human let-7 miRNA family consists of thirteen members that play critical roles in many biological processes, including development timing and tumor suppression, and their levels are disrupted in several diseases. Dicer is the endoribonuclease responsible for processing the precursor miRNA (pre-miRNA) to yield the mature miRNA, and thereby plays a crucial role in controlling the cellular levels of let-7 miRNAs. It is well established that the sequence and structural features of pre-miRNA hairpins such as the 5'-phosphate, the apical loop, and the 2-nt 3'-overhang are important for the processing activity of Dicer. Exceptionally, nine precursors of the let-7 family (pre-let-7) contain a 1-nt 3'-overhang and get mono-uridylated in vivo, presumably to allow efficient processing by Dicer. Pre-let-7 are also oligo-uridylated in vivo to promote their degradation and likely prevent their efficient processing by Dicer. In this study, we systematically investigated the impact of sequence and structural features of all human let-7 pre-miRNAs, including their 3'-end modifications, on Dicer binding and processing. Through the combination of SHAPE structural probing, in vitro binding and kinetic studies using purified human Dicer, we show that despite structural discrepancies among pre-let-7 RNAs, Dicer exhibits remarkable promiscuity in binding and cleaving these substrates. Moreover, the 1- or 2-nt 3'-overhang, 3'-mono-uridylation, and 3'-oligo-uridylation of pre-let-7 substrates appear to have little effect on Dicer binding and cleavage rates. Thus, this study extends current knowledge regarding the broad substrate specificity of Dicer and provides novel insight regarding the effect of 3'-modifications on binding and cleavage by Dicer.
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Affiliation(s)
- Gunjan Dadhwal
- Département de biochimie et médecine moléculaire, Université de Montréal, Downtown Station, Box 6128, Montreal, QC, H3C 3J7, Canada
| | - Hebatallah Samy
- Département de biochimie et médecine moléculaire, Université de Montréal, Downtown Station, Box 6128, Montreal, QC, H3C 3J7, Canada
| | - Jonathan Bouvette
- Département de biochimie et médecine moléculaire, Université de Montréal, Downtown Station, Box 6128, Montreal, QC, H3C 3J7, Canada
- Molecular Biology Department, Guyot Hall, Princeton University, Princeton, NJ, 08544, USA
| | - Fatima El-Azzouzi
- Département de biochimie et médecine moléculaire, Université de Montréal, Downtown Station, Box 6128, Montreal, QC, H3C 3J7, Canada
- Biochemistry Department, Wake Forest Biotech Place, 575 Patterson Avenue, Winston-Salem, NC, 27101, USA
| | - Pierre Dagenais
- Département de biochimie et médecine moléculaire, Université de Montréal, Downtown Station, Box 6128, Montreal, QC, H3C 3J7, Canada
| | - Pascale Legault
- Département de biochimie et médecine moléculaire, Université de Montréal, Downtown Station, Box 6128, Montreal, QC, H3C 3J7, Canada.
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Chamberlain AR, Huynh L, Huang W, Taylor DJ, Harris ME. The specificity landscape of bacterial ribonuclease P. J Biol Chem 2024; 300:105498. [PMID: 38013087 PMCID: PMC10731613 DOI: 10.1016/j.jbc.2023.105498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 11/14/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023] Open
Abstract
Developing quantitative models of substrate specificity for RNA processing enzymes is a key step toward understanding their biology and guiding applications in biotechnology and biomedicine. Optimally, models to predict relative rate constants for alternative substrates should integrate an understanding of structures of the enzyme bound to "fast" and "slow" substrates, large datasets of rate constants for alternative substrates, and transcriptomic data identifying in vivo processing sites. Such data are either available or emerging for bacterial ribonucleoprotein RNase P a widespread and essential tRNA 5' processing endonuclease, thus making it a valuable model system for investigating principles of biological specificity. Indeed, the well-established structure and kinetics of bacterial RNase P enabled the development of high throughput measurements of rate constants for tRNA variants and provided the necessary framework for quantitative specificity modeling. Several studies document the importance of conformational changes in the precursor tRNA substrate as well as the RNA and protein subunits of bacterial RNase P during binding, although the functional roles and dynamics are still being resolved. Recently, results from cryo-EM studies of E. coli RNase P with alternative precursor tRNAs are revealing prospective mechanistic relationships between conformational changes and substrate specificity. Yet, extensive uncharted territory remains, including leveraging these advances for drug discovery, achieving a complete accounting of RNase P substrates, and understanding how the cellular context contributes to RNA processing specificity in vivo.
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Affiliation(s)
| | - Loc Huynh
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Michael E Harris
- Department of Chemistry, University of Florida, Gainesville, Florida, USA.
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Torrez RM, Nagaraja S, Menon A, Chang L, Ohi MD, Garner AL. Comparative Biochemical Studies of Disease-Associated Human Dicer Mutations on Processing of a Pre-microRNA and snoRNA. Biochemistry 2023. [PMID: 37130292 DOI: 10.1021/acs.biochem.2c00687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Dicer is an RNase III enzyme that is responsible for the maturation of small RNAs such as microRNAs. As Dicer's cleavage products play key roles in promoting cellular homeostasis through the fine-tuning of gene expression, dysregulation of Dicer activity can lead to several human diseases, including cancers. Mutations in Dicer have been found to induce tumorigenesis and lead to the development of a rare pleiotropic tumor predisposition syndrome found in children and young adults called DICER1 syndrome. These patients harbor germline and somatic mutations in Dicer that lead to defective microRNA processing and activity. While most mutations occur within Dicer's catalytic RNase III domains, alterations within the Platform-PAZ (Piwi-Argonaute-Zwille) domain also cause loss of microRNA production. Using a combination of in vitro biochemical and cellular studies, we characterized the effect of disease-relevant Platform-PAZ-associated mutations on the processing of a well-studied oncogenic microRNA, pre-microRNA-21. We then compared these results to those of a representative from another Dicer substrate class, the small nucleolar RNA, snord37. From this analysis, we provide evidence that mutations within the Platform-PAZ domain result in differential impacts on RNA binding and processing, adding new insights into the complexities of Dicer processing of small RNA substrates.
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Affiliation(s)
- Rachel M Torrez
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States
| | - Shruti Nagaraja
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
| | - Arya Menon
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
| | - Louise Chang
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109, United States
| | - Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
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