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Liu M, Zhang Y, Jian Y, Gu L, Zhang D, Zhou H, Wang Y, Xu ZX. The regulations of telomerase reverse transcriptase (TERT) in cancer. Cell Death Dis 2024; 15:90. [PMID: 38278800 PMCID: PMC10817947 DOI: 10.1038/s41419-024-06454-7] [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: 09/22/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/28/2024]
Abstract
Abnormal activation of telomerase occurs in most cancer types, which facilitates escaping from cell senescence. As the key component of telomerase, telomerase reverse transcriptase (TERT) is regulated by various regulation pathways. TERT gene changing in its promoter and phosphorylation respectively leads to TERT ectopic expression at the transcription and protein levels. The co-interacting factors play an important role in the regulation of TERT in different cancer types. In this review, we focus on the regulators of TERT and these downstream functions in cancer regulation. Determining the specific regulatory mechanism will help to facilitate the development of a cancer treatment strategy that targets telomerase and cancer cell senescence. As the most important catalytic subunit component of telomerase, TERT is rapidly regulated by transcriptional factors and PTM-related activation. These changes directly influence TERT-related telomere maintenance by regulating telomerase activity in telomerase-positive cancer cells, telomerase assembly with telomere-binding proteins, and recruiting telomerase to the telomere. Besides, there are also non-canonical functions that are influenced by TERT, including the basic biological functions of cancer cells, such as proliferation, apoptosis, cell cycle regulation, initiating cell formation, EMT, and cell invasion. Other downstream effects are the results of the influence of transcriptional factors by TERT. Currently, some small molecular inhibitors of TERT and TERT vaccine are under research as a clinical therapeutic target. Purposeful work is in progress.
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Affiliation(s)
- Mingdi Liu
- Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, 130021, Jilin, China
| | - Yuning Zhang
- Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, 130021, Jilin, China
| | - Yongping Jian
- Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, 130021, Jilin, China
| | - Liting Gu
- Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, 130021, Jilin, China
| | - Dan Zhang
- Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, 130021, Jilin, China
| | - Honglan Zhou
- Department of Urology, The First Hospital of Jilin University, Changchun, 130021, Jilin, China.
| | - Yishu Wang
- Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, 130021, Jilin, China.
| | - Zhi-Xiang Xu
- Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, 130021, Jilin, China.
- Department of Urology, The First Hospital of Jilin University, Changchun, 130021, Jilin, China.
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Post-Transcriptional and Post-Translational Modifications in Telomerase Biogenesis and Recruitment to Telomeres. Int J Mol Sci 2023; 24:ijms24055027. [PMID: 36902458 PMCID: PMC10003056 DOI: 10.3390/ijms24055027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Telomere length is associated with the proliferative potential of cells. Telomerase is an enzyme that elongates telomeres throughout the entire lifespan of an organism in stem cells, germ cells, and cells of constantly renewed tissues. It is activated during cellular division, including regeneration and immune responses. The biogenesis of telomerase components and their assembly and functional localization to the telomere is a complex system regulated at multiple levels, where each step must be tuned to the cellular requirements. Any defect in the function or localization of the components of the telomerase biogenesis and functional system will affect the maintenance of telomere length, which is critical to the processes of regeneration, immune response, embryonic development, and cancer progression. An understanding of the regulatory mechanisms of telomerase biogenesis and activity is necessary for the development of approaches toward manipulating telomerase to influence these processes. The present review focuses on the molecular mechanisms involved in the major steps of telomerase regulation and the role of post-transcriptional and post-translational modifications in telomerase biogenesis and function in yeast and vertebrates.
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Fang YC, Fu SJ, Hsu PH, Chang PT, Huang JJ, Chiu YC, Liao YF, Jow GM, Tang CY, Jeng CJ. Identification of MKRN1 as a second E3 ligase for Eag1 potassium channels reveals regulation via differential degradation. J Biol Chem 2021; 296:100484. [PMID: 33647316 PMCID: PMC8039722 DOI: 10.1016/j.jbc.2021.100484] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 02/17/2021] [Accepted: 02/25/2021] [Indexed: 11/02/2022] Open
Abstract
Mutations in the human gene encoding the neuron-specific Eag1 voltage-gated K+ channel are associated with neurodevelopmental diseases, indicating an important role of Eag1 during brain development. A disease-causing Eag1 mutation is linked to decreased protein stability that involves enhanced protein degradation by the E3 ubiquitin ligase cullin 7 (CUL7). The general mechanisms governing protein homeostasis of plasma membrane- and endoplasmic reticulum (ER)-localized Eag1 K+ channels, however, remain unclear. By using yeast two-hybrid screening, we identified another E3 ubiquitin ligase, makorin ring finger protein 1 (MKRN1), as a novel binding partner primarily interacting with the carboxyl-terminal region of Eag1. MKRN1 mainly interacts with ER-localized immature core-glycosylated, as well as nascent nonglycosylated, Eag1 proteins. MKRN1 promotes polyubiquitination and ER-associated proteasomal degradation of immature Eag1 proteins. Although both CUL7 and MKRN1 contribute to ER quality control of immature core-glycosylated Eag1 proteins, MKRN1, but not CUL7, associates with and promotes degradation of nascent, nonglycosylated Eag1 proteins at the ER. In direct contrast to the role of CUL7 in regulating both ER and peripheral quality controls of Eag1, MKRN1 is exclusively responsible for the early stage of Eag1 maturation at the ER. We further demonstrated that both CUL7 and MKRN1 contribute to protein quality control of additional disease-causing Eag1 mutants associated with defective protein homeostasis. Our data suggest that the presence of this dual ubiquitination system differentially maintains Eag1 protein homeostasis and may ensure efficient removal of disease-associated misfolded Eag1 mutant channels.
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Affiliation(s)
- Ya-Ching Fang
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ssu-Ju Fu
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Hao Hsu
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Pei-Tzu Chang
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Jing-Jia Huang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Chih Chiu
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Fan Liao
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Guey-Mei Jow
- School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan
| | - Chih-Yung Tang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan.
| | - Chung-Jiuan Jeng
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Brain Research Center, National Yang-Ming University, Taipei, Taiwan.
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4
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Kotla S, Le NT, Vu HT, Ko KA, Gi YJ, Thomas TN, Giancursio C, Lusis AJ, Cooke JP, Fujiwara K, Abe JI. Endothelial senescence-associated secretory phenotype (SASP) is regulated by Makorin-1 ubiquitin E3 ligase. Metabolism 2019; 100:153962. [PMID: 31476350 PMCID: PMC7059097 DOI: 10.1016/j.metabol.2019.153962] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 08/02/2019] [Accepted: 08/21/2019] [Indexed: 12/23/2022]
Abstract
BACKGROUND Disturbed flow (d-flow)-induced senescence and activation of endothelial cells (ECs) have been suggested to have critical roles in promoting atherosclerosis. Telomeric repeat-binding factor 2 (TERF2)-interacting protein (TERF2IP), a member of the shelterin complex at the telomere, regulates the senescence-associated secretory phenotype (SASP), in which EC activation and senescence are engendered simultaneously by p90RSK-induced phosphorylation of TERF2IP S205 and subsequent nuclear export of the TERF2IP-TERF2 complex. In this study, we investigated TERF2IP-dependent gene expression and its role in regulating d-flow-induced SASP. METHODS A principal component analysis and hierarchical clustering were used to identify genes whose expression is regulated by TERF2IP in ECs under d-flow conditions. Senescence was determined by reduced telomere length, increased p53 and p21 expression, and increased apoptosis; EC activation was detected by NF-κB activation and the expression of adhesion molecules. The involvement of TERF2IP S205 phosphorylation in d-flow-induced SASP was assessed by depletion of TERF2IP and mutation of the phosphorylation site. RESULTS Our unbiased transcriptome analysis showed that TERF2IP caused alteration in the expression of a distinct set of genes, including rapamycin-insensitive companion of mTOR (RICTOR) and makorin-1 (MKRN1) ubiquitin E3 ligase, under d-flow conditions. In particular, both depletion of TERF2IP and overexpression of the TERF2IP S205A phosphorylation site mutant in ECs increased the d-flow and p90RSK-induced MKRN1 expression and subsequently inhibited apoptosis, telomere shortening, and NF-κB activation in ECs via suppression of p53, p21, and telomerase (TERT) induction. CONCLUSIONS MKRN1 and RICTOR belong to a distinct reciprocal gene set that is both negatively and positively regulated by p90RSK. TERF2IP S205 phosphorylation, a downstream event of p90RSK activation, uniquely inhibits MKRN1 expression and contributes to EC activation and senescence, which are key events for atherogenesis.
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Affiliation(s)
- Sivareddy Kotla
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Nhat-Tu Le
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, USA
| | - Hang Thi Vu
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Kyung Ae Ko
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Young Jin Gi
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tamlyn N Thomas
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Carolyn Giancursio
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Aldos J Lusis
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - John P Cooke
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, USA
| | - Keigi Fujiwara
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jun-Ichi Abe
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Hildebrandt A, Brüggemann M, Rücklé C, Boerner S, Heidelberger JB, Busch A, Hänel H, Voigt A, Möckel MM, Ebersberger S, Scholz A, Dold A, Schmid T, Ebersberger I, Roignant JY, Zarnack K, König J, Beli P. The RNA-binding ubiquitin ligase MKRN1 functions in ribosome-associated quality control of poly(A) translation. Genome Biol 2019; 20:216. [PMID: 31640799 PMCID: PMC6805484 DOI: 10.1186/s13059-019-1814-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 09/04/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Cells have evolved quality control mechanisms to ensure protein homeostasis by detecting and degrading aberrant mRNAs and proteins. A common source of aberrant mRNAs is premature polyadenylation, which can result in non-functional protein products. Translating ribosomes that encounter poly(A) sequences are terminally stalled, followed by ribosome recycling and decay of the truncated nascent polypeptide via ribosome-associated quality control. RESULTS Here, we demonstrate that the conserved RNA-binding E3 ubiquitin ligase Makorin Ring Finger Protein 1 (MKRN1) promotes ribosome stalling at poly(A) sequences during ribosome-associated quality control. We show that MKRN1 directly binds to the cytoplasmic poly(A)-binding protein (PABPC1) and associates with polysomes. MKRN1 is positioned upstream of poly(A) tails in mRNAs in a PABPC1-dependent manner. Ubiquitin remnant profiling and in vitro ubiquitylation assays uncover PABPC1 and ribosomal protein RPS10 as direct ubiquitylation substrates of MKRN1. CONCLUSIONS We propose that MKRN1 mediates the recognition of poly(A) tails to prevent the production of erroneous proteins from prematurely polyadenylated transcripts, thereby maintaining proteome integrity.
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Affiliation(s)
- Andrea Hildebrandt
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Mirko Brüggemann
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
| | - Cornelia Rücklé
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
| | - Susan Boerner
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
| | - Jan B Heidelberger
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Anke Busch
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Heike Hänel
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Andrea Voigt
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Martin M Möckel
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | | | - Anica Scholz
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Annabelle Dold
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Tobias Schmid
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Ingo Ebersberger
- Department for Applied Bioinformatics, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Max-von-Laue-Str. 13, 60438, Frankfurt am Main, Germany
- Senckenberg Biodiversity and Climate Research Centre (BiK-F), Georg-Voigt-Straße 14-16, 60325, Frankfurt am Main, Germany
| | - Jean-Yves Roignant
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Génopode Building, CH-1015, Lausanne, Switzerland
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany.
| | - Julian König
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany.
| | - Petra Beli
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany.
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Jeong EB, Jeong SS, Cho E, Kim EY. Makorin 1 is required for Drosophila oogenesis by regulating insulin/Tor signaling. PLoS One 2019; 14:e0215688. [PMID: 31009498 PMCID: PMC6476528 DOI: 10.1371/journal.pone.0215688] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 04/05/2019] [Indexed: 01/02/2023] Open
Abstract
Reproduction is a process that is extremely sensitive to changes in nutritional status. The nutritional control of oogenesis via insulin signaling has been reported; however, the mechanism underlying its sensitivity and tissue specificity has not been elucidated. Here, we determined that Drosophila Makorin RING finger protein 1 gene (Mkrn1) functions in the metabolic regulation of oogenesis. Mkrn1 was endogenously expressed at high levels in ovaries and Mkrn1 knockout resulted in female sterility. Mkrn1-null egg chambers were previtellogenic without egg production. FLP-FRT mosaic analysis revealed that Mkrn1 is essential in germline cells, but not follicle cells, for ovarian function. As well, AKT phosphorylation via insulin signaling was greatly reduced in the germline cells, but not the follicle cells, of the mutant clones in the ovaries. Furthermore, protein-rich diet elevated Mkrn1 protein levels, without increased mRNA levels. The p-AKT and p-S6K levels, downstream targets of insulin/Tor signaling, were significantly increased by a nutrient-rich diet in wild-type ovaries whereas those were low in Mkrn1exS compared to wild-type ovaries. Taken together, our results suggest that nutrient availability upregulates the Mkrn1 protein, which acts as a positive regulator of insulin signaling to confer sensitivity and tissue specificity in the ovaries for proper oogenesis based on nutritional status.
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Affiliation(s)
- Eui Beom Jeong
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Kyunggi-do, Republic of Korea
- Department of Brain Science, Ajou University School of Medicine, Suwon, Kyunggi-do, Republic of Korea
| | - Seong Su Jeong
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Kyunggi-do, Republic of Korea
- Department of Brain Science, Ajou University School of Medicine, Suwon, Kyunggi-do, Republic of Korea
| | - Eunjoo Cho
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Kyunggi-do, Republic of Korea
- Department of Brain Science, Ajou University School of Medicine, Suwon, Kyunggi-do, Republic of Korea
- * E-mail: (EYK); (EC)
| | - Eun Young Kim
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Kyunggi-do, Republic of Korea
- Department of Brain Science, Ajou University School of Medicine, Suwon, Kyunggi-do, Republic of Korea
- * E-mail: (EYK); (EC)
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The Long Non-Coding RNA lep-5 Promotes the Juvenile-to-Adult Transition by Destabilizing LIN-28. Dev Cell 2019; 49:542-555.e9. [PMID: 30956008 DOI: 10.1016/j.devcel.2019.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 10/02/2018] [Accepted: 03/06/2019] [Indexed: 12/28/2022]
Abstract
Biological roles for most long non-coding RNAs (lncRNAs) remain mysterious. Here, using forward genetics, we identify lep-5, a lncRNA acting in the C. elegans heterochronic (developmental timing) pathway. Loss of lep-5 delays hypodermal maturation and male tail tip morphogenesis (TTM), hallmarks of the juvenile-to-adult transition. We find that lep-5 is a ∼600 nt cytoplasmic RNA that is conserved across Caenorhabditis and possesses three essential secondary structure motifs but no essential open reading frames. lep-5 expression is temporally controlled, peaking prior to TTM onset. Like the Makorin LEP-2, lep-5 facilitates the degradation of LIN-28, a conserved miRNA regulator specifying the juvenile state. Both LIN-28 and LEP-2 associate with lep-5 in vivo, suggesting that lep-5 directly regulates LIN-28 stability and may function as an RNA scaffold. These studies identify a key biological role for a lncRNA: by regulating protein stability, it provides a temporal cue to facilitate the juvenile-to-adult transition.
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Yalçin Z, Selenz C, Jacobs JJL. Ubiquitination and SUMOylation in Telomere Maintenance and Dysfunction. Front Genet 2017; 8:67. [PMID: 28588610 PMCID: PMC5440461 DOI: 10.3389/fgene.2017.00067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 05/10/2017] [Indexed: 12/14/2022] Open
Abstract
Telomeres are essential nucleoprotein structures at linear chromosomes that maintain genome integrity by protecting chromosome ends from being recognized and processed as damaged DNA. In addition, they limit the cell’s proliferative capacity, as progressive loss of telomeric DNA during successive rounds of cell division eventually causes a state of telomere dysfunction that prevents further cell division. When telomeres become critically short, the cell elicits a DNA damage response resulting in senescence, apoptosis or genomic instability, thereby impacting on aging and tumorigenesis. Over the past years substantial progress has been made in understanding the role of post-translational modifications in telomere-related processes, including telomere maintenance, replication and dysfunction. This review will focus on recent findings that establish an essential role for ubiquitination and SUMOylation at telomeres.
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Affiliation(s)
- Zeliha Yalçin
- Department of Molecular Oncology, Netherlands Cancer InstituteAmsterdam, Netherlands
| | - Carolin Selenz
- Department of Molecular Oncology, Netherlands Cancer InstituteAmsterdam, Netherlands
| | - Jacqueline J L Jacobs
- Department of Molecular Oncology, Netherlands Cancer InstituteAmsterdam, Netherlands
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9
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Herrera RA, Kiontke K, Fitch DHA. Makorin ortholog LEP-2 regulates LIN-28 stability to promote the juvenile-to-adult transition in Caenorhabditis elegans. Development 2016; 143:799-809. [PMID: 26811380 DOI: 10.1242/dev.132738] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/16/2016] [Indexed: 12/27/2022]
Abstract
The heterochronic genes lin-28, let-7 and lin-41 regulate fundamental developmental transitions in animals, such as stemness versus differentiation and juvenile versus adult states. We identify a new heterochronic gene, lep-2, in Caenorhabditis elegans. Mutations in lep-2 cause a delay in the juvenile-to-adult transition, with adult males retaining pointed, juvenile tail tips, and displaying defective sexual behaviors. In both sexes, lep-2 mutants fail to cease molting or produce an adult cuticle. We find that LEP-2 post-translationally regulates LIN-28 by promoting LIN-28 protein degradation. lep-2 encodes the sole C. elegans ortholog of the Makorin (Mkrn) family of proteins. Like lin-28 and other heterochronic pathway members, vertebrate Mkrns are involved in developmental switches, including the timing of pubertal onset in humans. Based on shared roles, conservation and the interaction between lep-2 and lin-28 shown here, we propose that Mkrns, together with other heterochronic genes, constitute an evolutionarily ancient conserved module regulating switches in development.
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Affiliation(s)
| | - Karin Kiontke
- Department of Biology, New York University, New York, NY 10003, USA
| | - David H A Fitch
- Department of Biology, New York University, New York, NY 10003, USA Faculty of Arts and Sciences, New York University-Shanghai, Shanghai 200122, China
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10
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Cassar PA, Carpenedo RL, Samavarchi-Tehrani P, Olsen JB, Park CJ, Chang WY, Chen Z, Choey C, Delaney S, Guo H, Guo H, Tanner RM, Perkins TJ, Tenenbaum SA, Emili A, Wrana JL, Gibbings D, Stanford WL. Integrative genomics positions MKRN1 as a novel ribonucleoprotein within the embryonic stem cell gene regulatory network. EMBO Rep 2015; 16:1334-57. [PMID: 26265008 PMCID: PMC4670460 DOI: 10.15252/embr.201540974] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 07/15/2015] [Indexed: 02/04/2023] Open
Abstract
In embryonic stem cells (ESCs), gene regulatory networks (GRNs) coordinate gene expression to maintain ESC identity; however, the complete repertoire of factors regulating the ESC state is not fully understood. Our previous temporal microarray analysis of ESC commitment identified the E3 ubiquitin ligase protein Makorin‐1 (MKRN1) as a potential novel component of the ESC GRN. Here, using multilayered systems‐level analyses, we compiled a MKRN1‐centered interactome in undifferentiated ESCs at the proteomic and ribonomic level. Proteomic analyses in undifferentiated ESCs revealed that MKRN1 associates with RNA‐binding proteins, and ensuing RIP‐chip analysis determined that MKRN1 associates with mRNAs encoding functionally related proteins including proteins that function during cellular stress. Subsequent biological validation identified MKRN1 as a novel stress granule‐resident protein, although MKRN1 is not required for stress granule formation, or survival of unstressed ESCs. Thus, our unbiased systems‐level analyses support a role for the E3 ligase MKRN1 as a ribonucleoprotein within the ESC GRN.
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Affiliation(s)
- Paul A Cassar
- Institute of Medical Science University of Toronto, Toronto, ON, Canada Collaborative Program in Genome Biology and Bioinformatics, University of Toronto, Toronto, ON, Canada
| | - Richard L Carpenedo
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | | | - Jonathan B Olsen
- Collaborative Program in Genome Biology and Bioinformatics, University of Toronto, Toronto, ON, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Chang Jun Park
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Wing Y Chang
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Zhaoyi Chen
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON, Canada Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Chandarong Choey
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Sean Delaney
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON, Canada Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Huishan Guo
- Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Hongbo Guo
- Banting and Best Department of Medical Research, Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - R Matthew Tanner
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON, Canada Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Theodore J Perkins
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON, Canada Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Scott A Tenenbaum
- Colleges of Nanoscale Science & Engineering SUNY Polytechnic Institute, Albany, NY, USA
| | - Andrew Emili
- Collaborative Program in Genome Biology and Bioinformatics, University of Toronto, Toronto, ON, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada Banting and Best Department of Medical Research, Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Jeffrey L Wrana
- Collaborative Program in Genome Biology and Bioinformatics, University of Toronto, Toronto, ON, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada Center for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Derrick Gibbings
- Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, ON, Canada
| | - William L Stanford
- Institute of Medical Science University of Toronto, Toronto, ON, Canada Collaborative Program in Genome Biology and Bioinformatics, University of Toronto, Toronto, ON, Canada Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON, Canada Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, ON, Canada Ottawa Institute of Systems Biology, Ottawa, ON, Canada
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Ubiquitous expression of MAKORIN-2 in normal and malignant hematopoietic cells and its growth promoting activity. PLoS One 2014; 9:e92706. [PMID: 24675897 PMCID: PMC3968021 DOI: 10.1371/journal.pone.0092706] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 02/25/2014] [Indexed: 11/19/2022] Open
Abstract
Makorin-2 (MKRN2) is a highly conserved protein and yet its functions are largely unknown. We investigated the expression levels of MKRN2 and RAF1 in normal and malignant hematopoietic cells, and leukemia cell lines. We also attempted to delineate the role of MKRN2 in umbilical cord blood CD34+ stem/progenitor cells and K562 cell line by over-expression and inhibition of MKRN2 through lentivirus transduction and shRNA nucleofection, respectively. Our results provided the first evidence on the ubiquitous expression of MKRN2 in normal hematopoietic cells, embryonic stem cell lines, primary leukemia and leukemic cell lines of myeloid, lymphoid, erythroid and megakaryocytic lineages. The expression levels of MKRN2 were generally higher in primary leukemia samples compared with those in age-matched normal BM cells. In all leukemia subtypes, there was no significant correlation between expression levels of MKRN2 and RAF1. sh-MKRN2-silenced CD34+ cells had a significantly lower proliferation capacity and decreased levels of the early stem/progenitor subpopulation (CFU-GEMM) compared with control cultures. Over-expression of MKRN2 in K562 cells increased cell proliferation. Our results indicated possible roles of MKRN2 in normal and malignant hematopoiesis.
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Smallridge RC, Chindris AM, Asmann YW, Casler JD, Serie DJ, Reddi HV, Cradic KW, Rivera M, Grebe SK, Necela BM, Eberhardt NL, Carr JM, McIver B, Copland JA, Thompson EA. RNA sequencing identifies multiple fusion transcripts, differentially expressed genes, and reduced expression of immune function genes in BRAF (V600E) mutant vs BRAF wild-type papillary thyroid carcinoma. J Clin Endocrinol Metab 2014; 99:E338-47. [PMID: 24297791 PMCID: PMC3913813 DOI: 10.1210/jc.2013-2792] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
CONTEXT The BRAF V600E mutation (BRAF-MUT) confers an aggressive phenotype in papillary thyroid carcinoma, but unidentified additional genomic abnormalities may be required for full phenotypic expression. OBJECTIVE RNA sequencing (RNA-Seq) was performed to identify genes differentially expressed between BRAF-MUT and BRAF wild-type (BRAF-WT) tumors and to correlate changes to patient clinical status. DESIGN BRAF-MUT and BRAF-WT tumors were identified in patients with T1N0 and T2-3N1 tumors evaluated in a referral medical center. Gene expression levels were determined (RNA-Seq) and fusion transcripts were detected. Multiplexed capture/detection and digital counting of mRNA transcripts (nCounter, NanoString Technologies) validated RNA-Seq data for immune system-related genes. PATIENTS BRAF-MUT patients included nine women, three men; nine were TNM stage I and three were stage III. Three (25%) had tumor infiltrating lymphocytes. BRAF-WT included five women, three men; all were stage I, and five (62.5%) had tumor infiltrating lymphocytes. RESULTS RNA-Seq identified 560 of 13 085 genes differentially expressed between BRAF-MUT and BRAF-WT tumors. Approximately 10% of these genes were related to MetaCore immune function pathways; 51 were underexpressed in BRAF-MUT tumors, whereas 4 (HLAG, CXCL14, TIMP1, IL1RAP) were overexpressed. The four most differentially overexpressed immune genes in BRAF-WT tumors (IL1B; CCL19; CCL21; CXCR4) correlated with lymphocyte infiltration. nCounter confirmed the RNA-Seq expression level data. Eleven different high-confidence fusion transcripts were detected (four interchromosomal; seven intrachromosomal) in 13 of 20 tumors. All in-frame fusions were validated by RT-PCR. CONCLUSION BRAF-MUT papillary thyroid cancers have reduced expression of immune/inflammatory response genes compared with BRAF-WT tumors and correlate with lymphocyte infiltration. In contrast, HLA-G and CXCL14 are overexpressed in BRAF-MUT tumors. Sixty-five percent of tumors had between one and three fusion transcripts. Functional studies will be required to determine the potential role of these newly identified genomic abnormalities in contributing to the aggressiveness of BRAF-MUT and BRAF-WT tumors.
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Affiliation(s)
- Robert C Smallridge
- Department of Medicine (R.C.S.), Division of Endocrinology and Metabolism, Mayo Clinic, Jacksonville, Florida 32224; Department of Otorhinolaryngology-Head and Neck Surgery (A.M.C., J.D.C.), Mayo Clinic, Jacksonville, Florida 32224; Department of Health Sciences Research (Y.W.A., D.J.S.), Mayo Clinic, Jacksonville, Florida 32224; Department of Medicine, Division of Endocrinology (H.V.R., N.L.E., B.M.), Mayo Clinic, Rochester, Minnesota 55905; Department of Laboratory Medicine and Pathology (K.W.C., S.K.G.), Division of Clinical Biochemistry and Immunology, Mayo Clinic, Rochester, Minnesota 55905; Department of Laboratory Medicine and Pathology (M.R.), Division of Anatomic Pathology, Mayo Clinic, Rochester, Minnesota 55905; Department of Cancer Biology (B.N., J.M.C., J.A.C., E.A.T.), Mayo Clinic, Jacksonville, Florida 32224; and Department of Biochemistry and Molecular Biology (N.L.E.), Mayo Clinic, Rochester, Minnesota 55905
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Wadekar HB, Sahi VP, Morita EH, Abe S. MKRN expression pattern during embryonic and post-embryonic organogenesis in rice (Oryza sativa L. var. Nipponbare). PLANTA 2013; 237:1083-1095. [PMID: 23262670 DOI: 10.1007/s00425-012-1828-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 12/05/2012] [Indexed: 06/01/2023]
Abstract
Rice MKRN is a member of the makorin RING finger protein gene (MKRN) family, which encodes a protein with a characteristic array of zinc-finger motifs conserved in various eukaryotes. Using non-radioactive in situ hybridization, we investigated the spatio-temporal gene expression pattern of rice MKRN during embryogenesis, imbibition, seminal and lateral root development of Oryza sativa L. var. Nipponbare. MKRN expression was ubiquitous during early organogenesis in the embryo along the apical-basal and radial axes. The expression of MKRN decreased during embryonic organ elongation and maturation compared to early embryogenesis, but increased again during imbibition. Tissue-specific and position-dependent MKRN expression was found during embryonic and post-embryonic root and shoot development. Meristematic cells ubiquitously expressed MKRN transcripts, while differentiating cells showed a gradual reduction and termination of MKRN expression. Interestingly, during post-germination MKRN expression was prominent and continued in the metabolically active, differentiated companion cells of the phloem. The differential expression pattern was observed both in the differentiating and differentiated cells. Also, MKRN was expressed in the various developmental stages of the lateral root primordia and the cells surrounding them. Expression of MKRN was also observed after periclinal division of the presumptive pericycle founder cells. The MKRN expression pattern during development of various growth stages suggests an important role of makorin RING finger protein gene (MKRN) in embryonic and post-embryonic organogenesis in both apical-basal and radial developmental axes of rice.
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Affiliation(s)
- Hanumant Baburao Wadekar
- Laboratory of Molecular Cell Physiology, Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, 790-8566, Japan.
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The isoprenoid perillyl alcohol inhibits telomerase activity in prostate cancer cells. Biochimie 2012; 94:2639-48. [PMID: 22902867 DOI: 10.1016/j.biochi.2012.07.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Accepted: 07/31/2012] [Indexed: 12/16/2022]
Abstract
Isoprenoids are recognized for their ability to suppress carcinogenic processes in vivo and in vitro. We previously established that the isoprenoid, perillyl alcohol, acted mechanistically on translation of specific proteins through modulation of mechanistic target of rapamycin (mTOR) signaling. Telomerase-the enzyme responsible for immortalizing cells through the addition of telomeric repeats-is de-repressed early in an aspiring cancer cell. Here the effects of biologically-relevant concentrations and short incubations (1-16 h) of perillyl alcohol or the mTOR inhibitor, rapamycin, on telomerase activity were examined in prostate cancer cell lines. A rapid suppression of telomerase activity was observed (from ∼65% to >95%) determined by real-time quantitative telomerase repeat amplification protocol and confirmed by polyacrylamide gel-analysis. Using real-time reverse transcriptase-PCR, we demonstrated that human telomerase reverse transcriptase (hTERT) mRNA levels were unaltered. Western blot analysis revealed that hTERT protein levels decreased in response to perillyl alcohol or rapamycin. This decrease was partially blocked by pretreatment with a proteasome inhibitor MG-132, indicating that proteasomal degradation contributed to the loss of hTERT protein. No change in hTERT phosphorylation at Ser824 was observed, indicating the absence of cellular hTERT protein redistribution. These findings provide evidence for a unique link between nutrient- and macrolide-mediated regulation of mTOR and hTERT, a key enzyme that regulates DNA structure and stability.
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Abstract
Telomeres are stretches of repeated DNA sequences located at the ends of chromosomes that are necessary to prevent loss of gene-coding DNA regions during replication. Telomerase – the enzyme responsible for immortalising cancer cells through the addition of telomeric repeats – is active in ~90% of human cancers. Telomerase activity is inhibited by various phytochemicals such as isoprenoids, genistein, curcumin, epigallocatechin-3-gallate, resveratrol and others. Human TERT (telomerase reverse transcriptase – the rate-limiting component of telomerase), heat shock protein 90, Akt, p70 S6 kinase (S6K) and mammalian target of rapamycin (mTOR) form a physical and functional complex with one another. The inclusion of Akt, mTOR and S6K in the TERT complex is compelling evidence to support mTOR-mediated control of telomerase activity. This review will define the role of mTOR, the master regulator of protein translation, in telomerase regulation and provide additional insights into the numerous ways in which telomerase activity is hindered by phytochemicals.
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Regulation of the human catalytic subunit of telomerase (hTERT). Gene 2012; 498:135-46. [PMID: 22381618 DOI: 10.1016/j.gene.2012.01.095] [Citation(s) in RCA: 199] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 01/29/2012] [Accepted: 01/30/2012] [Indexed: 12/12/2022]
Abstract
Over the past decade, there has been much interest in the regulation of telomerase, the enzyme responsible for maintaining the integrity of chromosomal ends, and its crucial role in cellular immortalization, tumorigenesis, and the progression of cancer. Telomerase activity is characterized by the expression of the telomerase reverse transcriptase (TERT) gene, suggesting that TERT serves as the major limiting agent for telomerase activity. Recent discoveries have led to characterization of various interactants that aid in the regulation of human TERT (hTERT), including numerous transcription factors; further supporting the pivotal role that transcription plays in both the expression and repression of telomerase. Several studies have suggested that epigenetic modulation of the hTERT core promoter region may provide an additional level of regulation. Although these studies have provided essential information on the regulation of hTERT, there has been ambiguity of the role of methylation within the core promoter region and the subsequent binding of various activating and repressive agents. As a result, we found it necessary to consolidate and summarize these recent developments and elucidate these discrepancies. In this review, we focus on the co-regulation of hTERT via transcriptional regulation, the presence or absence of various activators and repressors, as well as the epigenetic pathways of DNA methylation and histone modifications.
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Chang CW, Cheng WC, Chen CR, Shu WY, Tsai ML, Huang CL, Hsu IC. Identification of human housekeeping genes and tissue-selective genes by microarray meta-analysis. PLoS One 2011; 6:e22859. [PMID: 21818400 PMCID: PMC3144958 DOI: 10.1371/journal.pone.0022859] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 06/29/2011] [Indexed: 01/26/2023] Open
Abstract
Background Categorizing protein-encoding transcriptomes of normal tissues into housekeeping genes and tissue-selective genes is a fundamental step toward studies of genetic functions and genetic associations to tissue-specific diseases. Previous studies have been mainly based on a few data sets with limited samples in each tissue, which restrained the representativeness of their identified genes, and resulted in low consensus among them. Results This study compiled 1,431 samples in 43 normal human tissues from 104 microarray data sets. We developed a new method to improve gene expression assessment, and showed that more than ten samples are needed to robustly identify the protein-encoding transcriptome of a tissue. We identified 2,064 housekeeping genes and 2,293 tissue-selective genes, and analyzed gene lists by functional enrichment analysis. The housekeeping genes are mainly involved in fundamental cellular functions, and the tissue-selective genes are strikingly related to functions and diseases corresponding to tissue-origin. We also compared agreements and related functions among our housekeeping genes and those of previous studies, and pointed out some reasons for the low consensuses. Conclusions The results indicate that sufficient samples have improved the identification of protein-encoding transcriptome of a tissue. Comprehensive meta-analysis has proved the high quality of our identified HK and TS genes. These results could offer a useful resource for future research on functional and genomic features of HK and TS genes.
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Affiliation(s)
- Cheng-Wei Chang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Wei-Chung Cheng
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Chaang-Ray Chen
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Wun-Yi Shu
- Institute of Statistics, National Tsing Hua University, Hsinchu, Taiwan
| | - Min-Lung Tsai
- Institute of Athletics, National Taiwan Sport University, Taichung, Taiwan
| | - Ching-Lung Huang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Ian C. Hsu
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
- * E-mail:
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Böhne A, Darras A, D'Cotta H, Baroiller JF, Galiana-Arnoux D, Volff JN. The vertebrate makorin ubiquitin ligase gene family has been shaped by large-scale duplication and retroposition from an ancestral gonad-specific, maternal-effect gene. BMC Genomics 2010; 11:721. [PMID: 21172006 PMCID: PMC3022923 DOI: 10.1186/1471-2164-11-721] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 12/20/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Members of the makorin (mkrn) gene family encode RING/C3H zinc finger proteins with U3 ubiquitin ligase activity. Although these proteins have been described in a variety of eukaryotes such as plants, fungi, invertebrates and vertebrates including human, almost nothing is known about their structural and functional evolution. RESULTS Via partial sequencing of a testis cDNA library from the poeciliid fish Xiphophorus maculatus, we have identified a new member of the makorin gene family, that we called mkrn4. In addition to the already described mkrn1 and mkrn2, mkrn4 is the third example of a makorin gene present in both tetrapods and ray-finned fish. However, this gene was not detected in mouse and rat, suggesting its loss in the lineage leading to rodent murids. Mkrn2 and mkrn4 are located in large ancient duplicated regions in tetrapod and fish genomes, suggesting the possible involvement of ancestral vertebrate-specific genome duplication in the formation of these genes. Intriguingly, many mkrn1 and mkrn2 intronless retrocopies have been detected in mammals but not in other vertebrates, most of them corresponding to pseudogenes. The nature and number of zinc fingers were found to be conserved in Mkrn1 and Mkrn2 but much more variable in Mkrn4, with lineage-specific differences. RT-qPCR analysis demonstrated a highly gonad-biased expression pattern for makorin genes in medaka and zebrafish (ray-finned fishes) and amphibians, but a strong relaxation of this specificity in birds and mammals. All three mkrn genes were maternally expressed before zygotic genome activation in both medaka and zebrafish early embryos. CONCLUSION Our analysis demonstrates that the makorin gene family has evolved through large-scale duplication and subsequent lineage-specific retroposition-mediated duplications in vertebrates. From the three major vertebrate mkrn genes, mkrn4 shows the highest evolutionary dynamics, with lineage-specific loss of zinc fingers and even complete gene elimination from certain groups of vertebrates. Comparative expression analysis strongly suggests that the ancestral E3 ubiquitin ligase function of the single copy mkrn gene before duplication in vertebrates was gonad-specific, with maternal expression in early embryos.
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Affiliation(s)
- Astrid Böhne
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS, INRA, Ecole Normale Supérieure de Lyon, Lyon, France.
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