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Mondragón-Rosas F, Florencio-Martínez LE, Villa-Delavequia GS, Manning-Cela RG, Carrero JC, Nepomuceno-Mejía T, Martínez-Calvillo S. Characterization of Tau95 led to the identification of a four-subunit TFIIIC complex in trypanosomatid parasites. Appl Microbiol Biotechnol 2024; 108:109. [PMID: 38204130 PMCID: PMC10781861 DOI: 10.1007/s00253-023-12903-8] [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: 07/05/2023] [Revised: 09/20/2023] [Accepted: 09/30/2023] [Indexed: 01/12/2024]
Abstract
RNA polymerase III (RNAP III) synthetizes small essential non-coding RNA molecules such as tRNAs and 5S rRNA. In yeast and vertebrates, RNAP III needs general transcription factors TFIIIA, TFIIIB, and TFIIIC to initiate transcription. TFIIIC, composed of six subunits, binds to internal promoter elements in RNAP III-dependent genes. Limited information is available about RNAP III transcription in the trypanosomatid protozoa Trypanosoma brucei and Leishmania major, which diverged early from the eukaryotic lineage. Analyses of the first published draft of the trypanosomatid genome sequences failed to recognize orthologs of any of the TFIIIC subunits, suggesting that this transcription factor is absent in these parasites. However, a putative TFIIIC subunit was recently annotated in the databases. Here we characterize this subunit in T. brucei and L. major and demonstrate that it corresponds to Tau95. In silico analyses showed that both proteins possess the typical Tau95 sequences: the DNA binding region and the dimerization domain. As anticipated for a transcription factor, Tau95 localized to the nucleus in insect forms of both parasites. Chromatin immunoprecipitation (ChIP) assays demonstrated that Tau95 binds to tRNA and U2 snRNA genes in T. brucei. Remarkably, by performing tandem affinity purifications we identified orthologs of TFIIIC subunits Tau55, Tau131, and Tau138 in T. brucei and L. major. Thus, contrary to what was assumed, trypanosomatid parasites do possess a TFIIIC complex. Other putative interacting partners of Tau95 were identified in T. brucei and L. major. KEY POINTS: • A four-subunit TFIIIC complex is present in T. brucei and L. major • TbTau95 associates with tRNA and U2 snRNA genes • Putative interacting partners of Tau95 might include some RNAP II regulators.
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Affiliation(s)
- Fabiola Mondragón-Rosas
- Facultad de Estudios Superiores Iztacala, Unidad de Biomedicina, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP 54090, México
| | - Luis E Florencio-Martínez
- Facultad de Estudios Superiores Iztacala, Unidad de Biomedicina, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP 54090, México
| | - Gino S Villa-Delavequia
- Facultad de Estudios Superiores Iztacala, Unidad de Biomedicina, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP 54090, México
| | - Rebeca G Manning-Cela
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Ciudad de Mexico, CP 07360, México
| | - Julio C Carrero
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de Mexico, 04510, México
| | - Tomás Nepomuceno-Mejía
- Facultad de Estudios Superiores Iztacala, Unidad de Biomedicina, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP 54090, México
| | - Santiago Martínez-Calvillo
- Facultad de Estudios Superiores Iztacala, Unidad de Biomedicina, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Edo. de México, CP 54090, México.
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2
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Sheng S, Chen B, Xu R, Han Y, Mao D, Chen Y, Li C, Su W, Hu X, Zhao Q, Lowe S, Huang Y, Shao W, Yao Y. A prognostic model for Schistosoma japonicum infection-associated liver hepatocellular carcinoma: strengthening the connection through initial biological experiments. Infect Agent Cancer 2024; 19:10. [PMID: 38515119 PMCID: PMC10956344 DOI: 10.1186/s13027-024-00569-4] [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: 12/15/2023] [Accepted: 02/28/2024] [Indexed: 03/23/2024] Open
Abstract
BACKGROUND Numerous studies have shown that Schistosoma japonicum infection correlates with an increased risk of liver hepatocellular carcinoma (LIHC). However, data regarding the role of this infection in LIHC oncogenesis are scarce. This study aimed to investigate the potential mechanisms of hepatocarcinogenesis associated with Schistosoma japonicum infection. METHODS By examining chronic liver disease as a mediator, we identified the genes contributing to Schistosoma japonicum infection and LIHC. We selected 15 key differentially expressed genes (DEGs) using weighted gene co-expression network analysis (WGCNA) and random survival forest models. Consensus clustering revealed two subgroups with distinct prognoses. Least Absolute Shrinkage and Selection Operator (LASSO) and Cox regression identified six prognostic DEGs, forming an Schistosoma japonicum infection-associated signature for strong prognosis prediction. This signature, which is an independent LIHC risk factor, was significantly correlated with clinical variables. Four DEGs, including BMI1, were selected based on their protein expression levels in cancerous and normal tissues. We confirmed BMI1's role in LIHC using Schistosoma japonicum-infected mouse models and molecular experiments. RESULTS We identified a series of DEGs that mediate schistosomiasis, the parasitic disease caused by Schistosoma japonicum infection, and hepatocarcinogenesis, and constructed a suitable prognostic model. We analyzed the mechanisms by which these DEGs regulate disease and present the differences in prognosis between the different genotypes. Finally, we verified our findings using molecular biology experiments. CONCLUSION Bioinformatics and molecular biology analyses confirmed a relationship between schistosomiasis and liver hepatocellular cancer. Furthermore, we validated the role of a potential oncoprotein factor that may be associated with infection and carcinogenesis. These findings enhance our understanding of Schistosoma japonicum infection's role in LIHC carcinogenesis.
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Affiliation(s)
- Shuyan Sheng
- First Clinical Medical College (First Affiliated Hospital), Anhui Medical University, Hefei, 230032, China
| | - Bangjie Chen
- First Clinical Medical College (First Affiliated Hospital), Anhui Medical University, Hefei, 230032, China
| | - Ruiyao Xu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, China
| | - Yanxun Han
- First Clinical Medical College (First Affiliated Hospital), Anhui Medical University, Hefei, 230032, China
| | - Deshen Mao
- First Clinical Medical College (First Affiliated Hospital), Anhui Medical University, Hefei, 230032, China
| | - Yuerong Chen
- First Clinical Medical College (First Affiliated Hospital), Anhui Medical University, Hefei, 230032, China
| | - Conghan Li
- First Clinical Medical College (First Affiliated Hospital), Anhui Medical University, Hefei, 230032, China
| | - Wenzhuo Su
- Second Clinical Medical College, Anhui Medical University, Hefei, 230032, China
| | - Xinyang Hu
- First Clinical Medical College (First Affiliated Hospital), Anhui Medical University, Hefei, 230032, China
| | - Qing Zhao
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, China
| | - Scott Lowe
- College of Osteopathic Medicine, Kansas City University, 1750 Independence Ave, Kansas City, MO, 64106, USA
| | - Yuting Huang
- Division of Gastroenterology and Hepatology, Mayo Clinic in Florida, Jacksonville, FL, USA
| | - Wei Shao
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, China.
| | - Yong Yao
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, China.
- School of Life Sciences, Anhui Medical University, Hefei, 230032, China.
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A nop56 Zebrafish Loss-of-Function Model Exhibits a Severe Neurodegenerative Phenotype. Biomedicines 2022; 10:biomedicines10081814. [PMID: 36009362 PMCID: PMC9404972 DOI: 10.3390/biomedicines10081814] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 11/17/2022] Open
Abstract
NOP56 belongs to a C/D box small nucleolar ribonucleoprotein complex that is in charge of cleavage and modification of precursor ribosomal RNAs and assembly of the 60S ribosomal subunit. An intronic expansion in NOP56 gene causes Spinocerebellar Ataxia type 36, a typical late-onset autosomal dominant ataxia. Although vertebrate animal models were created for the intronic expansion, none was studied for the loss of function of NOP56. We studied a zebrafish loss-of-function model of the nop56 gene which shows 70% homology with the human gene. We observed a severe neurodegenerative phenotype in nop56 mutants, characterized mainly by absence of cerebellum, reduced numbers of spinal cord neurons, high levels of apoptosis in the central nervous system (CNS) and impaired movement, resulting in death before 7 days post-fertilization. Gene expression of genes related to C/D box complex, balance and CNS development was impaired in nop56 mutants. In our study, we characterized the first NOP56 loss-of-function vertebrate model, which is important to further understand the role of NOP56 in CNS function and development.
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Nepomuceno-Mejía T, Florencio-Martínez LE, Pineda-García I, Martínez-Calvillo S. Identification of factors involved in ribosome assembly in the protozoan parasite Leishmania major. Acta Trop 2022; 228:106315. [PMID: 35041807 DOI: 10.1016/j.actatropica.2022.106315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/07/2022] [Accepted: 01/13/2022] [Indexed: 01/23/2023]
Abstract
Formation of the ribosome subunits is a complex and progressive cellular process that requires a plethora of non-ribosomal transient proteins and diverse small nucleolar RNAs, which are involved from the synthesis of the precursor ribosomal RNA in the nucleolus to the final ribosome processing steps in the cytoplasm. Employing PTP-tagged Nop56 as a fishing bait to capture pre-ribosomal particles by tandem affinity purifications, mass spectrometry assays and a robust in silico analysis, here we describe tens of ribosome assembly factors involved in the synthesis of both ribosomal subunits in the human pathogen Leishmania major, where the knowledge about ribosomal biogenesis is scarce. We identified a large number of proteins that participate in most stages of ribosome biogenesis in yeast and mammals. Among them, we found several putative orthologs of factors not previously identified in L. major, such as t-Utp4, t-Utp5, Rrp7, Nop9 and Nop15. Even more interesting is the fact that we identified several novel candidates that could participate in the assembly of the atypical 60S subunit in L. major, which contains eight different rRNA species. As these proteins do not seem to have a human counterpart, they have potential as targets for novel anti-leishmanial drugs. Also, numerous proteins whose function is not apparently linked to ribosome assembly were copurified, suggesting that the L. major nucleolus is a multifunctional nuclear body.
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Assis LHC, Andrade-Silva D, Shiburah ME, de Oliveira BCD, Paiva SC, Abuchery BE, Ferri YG, Fontes VS, de Oliveira LS, da Silva MS, Cano MIN. Cell Cycle, Telomeres, and Telomerase in Leishmania spp.: What Do We Know So Far? Cells 2021; 10:cells10113195. [PMID: 34831418 PMCID: PMC8621916 DOI: 10.3390/cells10113195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/12/2021] [Accepted: 11/14/2021] [Indexed: 12/18/2022] Open
Abstract
Leishmaniases belong to the inglorious group of neglected tropical diseases, presenting different degrees of manifestations severity. It is caused by the transmission of more than 20 species of parasites of the Leishmania genus. Nevertheless, the disease remains on the priority list for developing new treatments, since it affects millions in a vast geographical area, especially low-income people. Molecular biology studies are pioneers in parasitic research with the aim of discovering potential targets for drug development. Among them are the telomeres, DNA–protein structures that play an important role in the long term in cell cycle/survival. Telomeres are the physical ends of eukaryotic chromosomes. Due to their multiple interactions with different proteins that confer a likewise complex dynamic, they have emerged as objects of interest in many medical studies, including studies on leishmaniases. This review aims to gather information and elucidate what we know about the phenomena behind Leishmania spp. telomere maintenance and how it impacts the parasite’s cell cycle.
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Affiliation(s)
- Luiz H. C. Assis
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Débora Andrade-Silva
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Mark E. Shiburah
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Beatriz C. D. de Oliveira
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Stephany C. Paiva
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Bryan E. Abuchery
- DNA Replication and Repair Laboratory (DRRL), Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (B.E.A.); (Y.G.F.)
| | - Yete G. Ferri
- DNA Replication and Repair Laboratory (DRRL), Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (B.E.A.); (Y.G.F.)
| | - Veronica S. Fontes
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Leilane S. de Oliveira
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Marcelo S. da Silva
- DNA Replication and Repair Laboratory (DRRL), Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (B.E.A.); (Y.G.F.)
- Correspondence: (M.S.d.S.); (M.I.N.C.)
| | - Maria Isabel N. Cano
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
- Correspondence: (M.S.d.S.); (M.I.N.C.)
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Bílý T, Sheikh S, Mallet A, Bastin P, Pérez-Morga D, Lukeš J, Hashimi H. Ultrastructural Changes of the Mitochondrion During the Life Cycle of Trypanosoma brucei. J Eukaryot Microbiol 2021; 68:e12846. [PMID: 33624359 DOI: 10.1111/jeu.12846] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/04/2021] [Accepted: 02/15/2021] [Indexed: 11/29/2022]
Abstract
The mitochondrion is crucial for ATP generation by oxidative phosphorylation, among other processes. Cristae are invaginations of the mitochondrial inner membrane that house nearly all the macromolecular complexes that perform oxidative phosphorylation. The unicellular parasite Trypanosoma brucei undergoes during its life cycle extensive remodeling of its single mitochondrion, which reflects major changes in its energy metabolism. While the bloodstream form (BSF) generates ATP exclusively by substrate-level phosphorylation and has a morphologically highly reduced mitochondrion, the insect-dwelling procyclic form (PCF) performs oxidative phosphorylation and has an expanded and reticulated organelle. Here, we have performed high-resolution 3D reconstruction of BSF and PCF mitochondria, with a particular focus on their cristae. By measuring the volumes and surface areas of these structures in complete or nearly complete cells, we have found that mitochondrial cristae are more prominent in BSF than previously thought and their biogenesis seems to be maintained during the cell cycle. Furthermore, PCF cristae exhibit a surprising range of volumes in situ, implying that each crista is acting as an independent bioenergetic unit. Cristae appear to be particularly enriched in the region of the organelle between the nucleus and kinetoplast, the mitochondrial genome, suggesting this part has distinctive properties.
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Affiliation(s)
- Tomáš Bílý
- Institute of Parasitology, Biology Center, Czech Academy of Sciences & Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Shaghayegh Sheikh
- Institute of Parasitology, Biology Center, Czech Academy of Sciences & Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Adeline Mallet
- Trypanosome Cell Biology Unit & INSERM U1201, Institut Pasteur, Paris, France.,Ultrastructural Bio Imaging Unit, C2RT, Institut Pasteur & Sorbonne Université école doctorale complexité du vivant, ED 515, Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit & INSERM U1201, Institut Pasteur, Paris, France
| | - David Pérez-Morga
- Laboratory of Molecular Parasitology, IBMM & Center for Microscopy and Molecular Imaging, Université Libre de Bruxelles, Brussels, Belgium
| | - Julius Lukeš
- Institute of Parasitology, Biology Center, Czech Academy of Sciences & Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Hassan Hashimi
- Institute of Parasitology, Biology Center, Czech Academy of Sciences & Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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Participation of TFIIIB Subunit Brf1 in Transcription Regulation in the Human Pathogen Leishmania major. Genes (Basel) 2021; 12:genes12020280. [PMID: 33669344 PMCID: PMC7920299 DOI: 10.3390/genes12020280] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/02/2021] [Accepted: 02/11/2021] [Indexed: 12/24/2022] Open
Abstract
In yeast and higher eukaryotes, transcription factor TFIIIB is required for accurate initiation of transcription by RNA Polymerase III (Pol III), which synthesizes transfer RNAs (tRNAs), 5S ribosomal RNA (rRNA), and other essential RNA molecules. TFIIIB is composed of three subunits: B double prime 1 (Bdp1), TATA-binding protein (TBP), and TFIIB-related factor 1 (Brf1). Here, we report the molecular characterization of Brf1 in Leishmania major (LmBrf1), a parasitic protozoan that shows distinctive transcription characteristics, including the apparent absence of Pol III general transcription factors TFIIIA and TFIIIC. Although single-knockout parasites of LmBrf1 were obtained, attempts to generate LmBrf1-null mutants were unsuccessful, which suggests that LmBrf1 is essential in promastigotes of L. major. Notably, Northern blot analyses showed that the half-lives of the messenger RNAs (mRNAs) from LmBrf1 and other components of the Pol III transcription machinery (Bdp1 and Pol III subunit RPC1) are very similar (~40 min). Stabilization of these transcripts was observed in stationary-phase parasites. Chromatin immunoprecipitation (ChIP) experiments showed that LmBrf1 binds to tRNA, small nuclear RNA (snRNA), and 5S rRNA genes. Unexpectedly, the results also indicated that LmBrf1 associates to the promoter region of the 18S rRNA genes and to three Pol II-dependent regions here analyzed. Tandem affinity purification and mass spectrometry analyses allowed the identification of a putative TFIIIC subunit. Moreover, several proteins involved in transcription by all three RNA polymerases co-purified with the tagged version of LmBrf1.
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Martínez-Calvillo S, Florencio-Martínez LE, Nepomuceno-Mejía T. Nucleolar Structure and Function in Trypanosomatid Protozoa. Cells 2019; 8:cells8050421. [PMID: 31071985 PMCID: PMC6562600 DOI: 10.3390/cells8050421] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 04/26/2019] [Accepted: 04/28/2019] [Indexed: 12/12/2022] Open
Abstract
The nucleolus is the conspicuous nuclear body where ribosomal RNA genes are transcribed by RNA polymerase I, pre-ribosomal RNA is processed, and ribosomal subunits are assembled. Other important functions have been attributed to the nucleolus over the years. Here we review the current knowledge about the structure and function of the nucleolus in the trypanosomatid parasites Trypanosoma brucei, Trypanosoma cruzi and Leishmania ssp., which represent one of the earliest branching lineages among the eukaryotes. These protozoan parasites present a single nucleolus that is preserved throughout the closed nuclear division, and that seems to lack fibrillar centers. Trypanosomatids possess a relatively low number of rRNA genes, which encode rRNA molecules that contain large expansion segments, including several that are trypanosomatid-specific. Notably, the large subunit rRNA (28S-type) is fragmented into two large and four small rRNA species. Hence, compared to other organisms, the rRNA primary transcript requires additional processing steps in trypanosomatids. Accordingly, this group of parasites contains the highest number ever reported of snoRNAs that participate in rRNA processing. The number of modified rRNA nucleotides in trypanosomatids is also higher than in other organisms. Regarding the structure and biogenesis of the ribosomes, recent cryo-electron microscopy analyses have revealed several trypanosomatid-specific features that are discussed here. Additional functions of the nucleolus in trypanosomatids are also reviewed.
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Affiliation(s)
- Santiago Martínez-Calvillo
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla CP 54090, Estado de México, Mexico.
| | - Luis E Florencio-Martínez
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla CP 54090, Estado de México, Mexico.
| | - Tomás Nepomuceno-Mejía
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla CP 54090, Estado de México, Mexico.
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9
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Román-Carraro FC, Florencio-Martínez LE, Romero-Meza G, Nepomuceno-Mejía T, Carrero JC, Arroyo R, Ortega-López J, Manning-Cela RG, Martínez-Calvillo S. TFIIIB Subunit Bdp1 Participates in RNA Polymerase III Transcription in the Protozoan Parasite Leishmania major. BIOMED RESEARCH INTERNATIONAL 2019; 2019:1425281. [PMID: 31058184 PMCID: PMC6463643 DOI: 10.1155/2019/1425281] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 03/13/2019] [Indexed: 01/03/2023]
Abstract
Leishmania major, a protozoan parasite that diverged early from the main eukaryotic lineage, exhibits unusual mechanisms of gene expression. Little is known in this organism about the transcription factors involved in the synthesis of tRNA, 5S rRNA, and snRNAs, transcribed by RNA Polymerase III (Pol III). Here we identify and characterize the TFIIIB subunit Bdp1 in L. major (LmBdp1). Bdp1 plays key roles in Pol III transcription initiation in other organisms, as it participates in Pol III recruitment and promoter opening. In silico analysis showed that LmBdp1 contains the typical extended SANT domain as well as other Bdp1 conserved regions. Nevertheless, LmBdp1 also displays distinctive features, including the presence of only one aromatic residue in the N-linker region. We were not able to produce null mutants of LmBdp1 by homologous recombination, as the obtained double replacement cell line contained an extra copy of LmBdp1, indicating that LmBdp1 is essential for the viability of L. major promastigotes. Notably, the mutant cell line showed reduced levels of the LmBdp1 protein, and its growth was significantly decreased in relation to wild-type cells. Nuclear run-on assays demonstrated that Pol III transcription was affected in the mutant cell line, and ChIP experiments showed that LmBdp1 binds to 5S rRNA, tRNA, and snRNA genes. Thus, our results indicate that LmBdp1 is an essential protein required for Pol III transcription in L. major.
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Affiliation(s)
- Fiordaliso C. Román-Carraro
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
| | - Luis E. Florencio-Martínez
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
| | - Gabriela Romero-Meza
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
| | - Tomás Nepomuceno-Mejía
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
| | - Julio C. Carrero
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, CP 04510, Mexico
| | - Rossana Arroyo
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Ciudad de México, CP 07360, Mexico
| | - Jaime Ortega-López
- Departamento de Biotecnología y Bioingeniería, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Ciudad de México, CP 07360, Mexico
| | - Rebeca G. Manning-Cela
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Ciudad de México, CP 07360, Mexico
| | - Santiago Martínez-Calvillo
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
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