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Primary Structure and Coding Genes of Two Pheromones from the Antarctic Psychrophilic Ciliate, Euplotes focardii. Microorganisms 2022; 10:microorganisms10061089. [PMID: 35744607 PMCID: PMC9229436 DOI: 10.3390/microorganisms10061089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/14/2022] [Accepted: 05/23/2022] [Indexed: 02/01/2023] Open
Abstract
In ciliates, diffusible cell type-specific pheromones regulate cell growth and mating phenomena acting competitively in both autocrine and heterologous fashion. In Euplotes species, these signaling molecules are represented by species-specific families of structurally homologous small, disulfide-rich proteins, each specified by one of a series of multiple alleles that are inherited without relationships of dominance at the mat-genetic locus of the germinal micronuclear genome, and expressed as individual gene-sized molecules in the somatic macronuclear genome. Here we report the 85-amino acid sequences and the full-length macronuclear nucleotide coding sequences of two pheromones, designated Ef-1 and Ef-2, isolated from the supernatant of a wild-type strain of a psychrophilic species of Euplotes, E. focardii, endemic to Antarctic coastal waters. An overall comparison of the determined E. focardii pheromone and pheromone-gene structures with their homologs from congeneric species provides an initial picture of how an evolutionary increase in the complexity of these structures accompanies Euplotes speciation.
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Conjugation in Euplotes raikovi (Protista, Ciliophora): New Insights into Nuclear Events and Macronuclear Development from Micronucleate and Amicronucleate Cells. Microorganisms 2020; 8:microorganisms8020162. [PMID: 31979289 PMCID: PMC7074782 DOI: 10.3390/microorganisms8020162] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 01/08/2023] Open
Abstract
Ciliates form a distinct group of single-celled eukaryotes that host two types of nuclei (micro and macronucleus) in the same cytoplasm and have a special sexual process known as conjugation, which involves mitosis, meiosis, fertilization, nuclear differentiation, and development. Due to their high species diversity, ciliates have evolved different patterns of nuclear events during conjugation. In the present study, we investigate these events in detail in the marine species Euplotes raikovi. Our results indicate that: (i) conjugation lasts for about 50 h, the longest stage being the development of the new macronucleus (ca. 36 h); (ii) there are three prezygotic micronuclear divisions (mitosis and meiosis I and II) and two postzygotic synkaryon divisions; and (iii) a fragment of the parental macronucleus fuses with the new developing macronucleus. In addition, we describe for the first time conjugation in amicronucleate E. raikovi cells. When two amicronucleate cells mate, they separate after about 4 h without evident nuclear changes; when one amicronucleate cell mates with a micronucleate cell, the micronucleus undergoes regular prezygotic divisions to form migratory and stationary pronuclei, but the two pronuclei fuse in the same cell. In the amicronucleate cell, the parental macronucleus breaks into fragments, which are then recovered to form a new functional macronucleus. These results add new information on the process of conjugation in both micronucleate and amicronucleate Euplotes cells.
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Jiang Y, Zhang T, Vallesi A, Yang X, Gao F. Time-course analysis of nuclear events during conjugation in the marine ciliate Euplotes vannus and comparison with other ciliates (Protozoa, Ciliophora). Cell Cycle 2019; 18:288-298. [PMID: 30563432 DOI: 10.1080/15384101.2018.1558871] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ciliates represent a morphologically and genetically distinct group of single-celled eukaryotes that segregate germline and somatic functions into two types of nuclei and exhibit complex cytogenetic events during the sexual process of conjugation, which is under the control of the so-called "mating type systems". Studying conjugation in ciliates may provide insight into our understanding of the origins and evolution of sex and fertilization. In the present work, we studied in detail the sexual process of conjugation using the model species Euplotes vannus, and compared these nuclear events with those occurring in other ciliates. Our results indicate that in E. vannus: 1) conjugation requires about 75 hours to complete: the longest step is the development of the new macronucleus (ca. 64h), followed by the nuclear division of meiosis I (5h); the mitotic divisions usually take only 2h; 2) there are three prezygotic divisions (mitosis and meiosis I and II), and two of the eight resulting nuclei become pronuclei; 3) after the exchange and fusion of the pronuclei, two postzygotic divisions occur; two of the four products differentiate into the new micronucleus and macronucleus, respectively, and the parental macronucleus degenerates completely; 4) comparison of the nuclear events during conjugation in different ciliates reveals that there are generally three prezygotic divisions while the number of postzygotic divisions is highly variable. These results can serve as reference to investigate the mating type system operating in this species and to analyze genes involved in the different steps of the sexual process.
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Affiliation(s)
- Yaohan Jiang
- a Institute of Evolution and Marine Biodiversity , Ocean University of China , Qingdao , China.,b Ministry of Education , Key Laboratory of Mariculture (Ocean University of China) , Qingdao , China
| | - Tengteng Zhang
- a Institute of Evolution and Marine Biodiversity , Ocean University of China , Qingdao , China.,b Ministry of Education , Key Laboratory of Mariculture (Ocean University of China) , Qingdao , China
| | - Adriana Vallesi
- c Laboratory of Eukaryotic Microbiology and Animal Biology , University of Camerino , Camerino , Italy
| | - Xianyu Yang
- d College of Animal Science and Technology , Zhejiang A&F University , Hangzhou , China
| | - Feng Gao
- a Institute of Evolution and Marine Biodiversity , Ocean University of China , Qingdao , China.,b Ministry of Education , Key Laboratory of Mariculture (Ocean University of China) , Qingdao , China
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Ricci F, Candelori A, Brandi A, Alimenti C, Luporini P, Vallesi A. The Sub-Chromosomic Macronuclear Pheromone Genes of the Ciliate Euplotes raikovi: Comparative Structural Analysis and Insights into the Mechanism of Expression. J Eukaryot Microbiol 2018; 66:376-384. [PMID: 30076754 DOI: 10.1111/jeu.12677] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/16/2018] [Accepted: 07/25/2018] [Indexed: 12/23/2022]
Abstract
In Euplotes raikovi, we have determined the full-length sequences of a family of macronuclear genes that are the transcriptionally active versions of codominant alleles inherited at the mating-type (mat) locus of the micronuclear genome, and encode cell type-distinctive signaling pheromones. These genes include a 225-231-bp coding region flanked by a conserved 544-bp 5'-leader region and a more variable 3'-trailer region. Two transcription initiation start sites and two polyadenylation sites associated with nonconventional signals cooperate with a splicing phenomenon of a 326-bp intron residing in the 5'-leader region in the generation of multiple transcripts from the same gene. In two of them, the synthesis of functional products depends on the reassignment to a sense codon, or readthrough of a strictly conserved leaky UAG stop codon. That this reassignment may take place is suggested by the position this codon occupies in the transcripts, close to the transcript extremity and far from the poly(A) tail. In such a case, one product is a 69-amino acid protein in search of function and the second product is a 126-amino acid protein that represents a membrane-bound pheromone isoform candidate to function as a cell type-specific binding site (receptor) of the soluble pheromones.
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Affiliation(s)
- Francesca Ricci
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Annalisa Candelori
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Anna Brandi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Claudio Alimenti
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Pierangelo Luporini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
| | - Adriana Vallesi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino (MC), 62032, Italy
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Iwasa Y, Sasaki A. EVOLUTION OF THE NUMBER OF SEXES. Evolution 2017; 41:49-65. [DOI: 10.1111/j.1558-5646.1987.tb05770.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/1985] [Accepted: 08/22/1986] [Indexed: 11/29/2022]
Affiliation(s)
- Yoh Iwasa
- Department of Biology, Faculty of Science; Kyushu University; Fukuoka 812 Japan
| | - Akira Sasaki
- Department of Biology, Faculty of Science; Kyushu University; Fukuoka 812 Japan
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Vallesi A, Alimenti C, Federici S, Di Giuseppe G, Dini F, Guella G, Luporini P. Evidence for gene duplication and allelic codominance (not hierarchical dominance) at the mating-type locus of the ciliate, Euplotes crassus. J Eukaryot Microbiol 2014; 61:620-9. [PMID: 25040318 DOI: 10.1111/jeu.12140] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/25/2014] [Accepted: 05/03/2014] [Indexed: 11/30/2022]
Abstract
The high-multiple mating system of Euplotes crassus is known to be controlled by multiple alleles segregating at a single locus and manifesting relationships of hierarchical dominance, so that heterozygous cells would produce a single mating-type substance (pheromone). In strain L-2D, now known to be homozygous at the mating-type locus, we previously identified two pheromones (Ec-α and Ec-1) characterized by significant variations in their amino acid sequences and structure of their macronuclear coding genes. In this study, pheromones and macronuclear coding genes have been analyzed in strain POR-73 characterized by a heterozygous genotype and strong mating compatibility with L-2D strain. It was found that POR-73 cells contain three distinct pheromone coding genes and, accordingly, secrete three distinct pheromones. One pheromone revealed structural identity in amino acid sequence and macronuclear coding gene to the Ec-α pheromone of L-2D cells. The other two pheromones were shown to be new and were designated Ec-2 and Ec-3 to denote their structural homology with the Ec-1 pheromone of L-2D cells. We interpreted these results as evidence of a phenomenon of gene duplication at the E. crassus mating-type locus, and lack of hierarchical dominance in the expression of the macronuclear pheromone genes in cells with heterozygous genotypes.
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Affiliation(s)
- Adriana Vallesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, University of Camerino, 62032, Camerino, MC, Italy
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Alimenti C, Vallesi A, Federici S, di Giuseppe G, Fernando D, Carratore V, Luporini P. Isolation and structural characterization of two water-borne pheromones from Euplotes crassus, a ciliate commonly known to carry membrane-bound pheromones. J Eukaryot Microbiol 2011; 58:234-41. [PMID: 21414056 DOI: 10.1111/j.1550-7408.2011.00535.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ciliates comprise species synthesizing water-diffusible mating type factors or pheromones and species synthesizing insoluble, cell membrane-bound pheromones. Euplotes crassus has traditionally been placed in the latter group. In contrast with this notion, we found that E. crassus is a constitutive pheromone-secreting ciliate, like other Euplotes species. From cell-free filtrate preparations of the E. crassus strain L-2D, we isolated two distinct pheromones, designated as Ec-α and Ec-1, and determined their complete amino acid sequences by combined chemical and genetic approaches. The Ec-α pheromone sequence extends for 56 amino acid residues with six cysteines and shows a molecular mass of 6,183 Da, while the Ec-1 pheromone sequence extends for 45 amino acid residues with 10 cysteines and shows a molecular mass of 4,840 Da. Marked structural differences distinguish the full-length Ec-α and Ec-1 coding sequences, which have been cloned and characterized from the transcriptionally active macronuclear genome. They were taken as clear indication that the Ec-α and Ec-1 pheromones are specified by genes that are not allelic, but likely derived from a duplicated genetic locus of the transcriptionally silent micronuclear genome.
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Affiliation(s)
- Claudio Alimenti
- Dipartimento di Scienze Ambientali e Naturali, University of Camerino, 62032 Camerino (MC), Italy
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Valbonesi A, Ortenzi C, Luporini P. Observations on the biology ofEuplotes charon(Hypotrichida, Ciliophora). ACTA ACUST UNITED AC 2009. [DOI: 10.1080/11250008709355569] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Alessandro Valbonesi
- a Dipartimento di Biologia Cellulare , Università di Camerino , Via Camerini 2, Camerino, 62032, Italy
| | - Claudio Ortenzi
- a Dipartimento di Biologia Cellulare , Università di Camerino , Via Camerini 2, Camerino, 62032, Italy
| | - Pierangelo Luporini
- a Dipartimento di Biologia Cellulare , Università di Camerino , Via Camerini 2, Camerino, 62032, Italy
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GATES MICHAELA. Morphological Drift Accompanying Nascent Population Differentiation in the CiliateEuplotes vannus. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1990.tb05874.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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VALBONESI ALESSANDRO, ORTENZI CLAUDIO, LUPORINI PIERANGELO. The Species Problem in a Ciliate with a High Multiple Mating Type System,Euplotes crassus. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1992.tb01282.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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DINI FERNANDO, BLEYMAN LEAK, GIUBBILINI PAOLA. Non-Mendelian Inheritance of Early Maturity inEuplotes crassus. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1990.tb01250.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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VALBONESI A, ORTENZI C, LUPORINI P. An Integrated Study of the Species Problem in theEuplotes crassus-minuta-vannusGroup1. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1988.tb04073.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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DINI FERNANDO, BRACCHI PAOLO, GIANNÍ ALESSANDRO. Mating Types inAspidiscasp. (Ciliophora, Hypotrichida): a Cluster of Cryptic Species. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1987.tb03165.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Brünen-Nieweier C, Christoph Weiligmann J, Hansen B, Kuhlmann HW, Möllenbeck M, Heckmann K. The pheromones and pheromone genes of new stocks of the Euplotes octocarinatus species complex. Eur J Protistol 1998. [DOI: 10.1016/s0932-4739(98)80022-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Affiliation(s)
- G Beale
- Genetics Department, University of Edinburgh, UK
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Raffioni S, Luporini P, Chait BT, Disper SS, Bradshaw RA. Primary structure of the mating pheromone Er-1 of the ciliate Euplotes raikovi. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)81338-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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18
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Raffioni S, Miceli C, Concetti A, Barra D, Luporini P. Purification and characterization of new mating pheromones of the ciliate Euplotes raikovi. Exp Cell Res 1987; 172:417-24. [PMID: 3115800 DOI: 10.1016/0014-4827(87)90399-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Cell union in mating pairs in the ciliate Euplotes raikovi is controlled by a system of multiple mating types which are inherited with alleles codominant at the genetic locus mat and expressed via diffusible mating pheromones. The mating pheromones Er-2, Er-3, and Er-11 were purified from cells homozygous for the mat-2, mat-3, and mat-11 alleles, respectively. These pheromones are proteins of similar Mr (11,000-12,000) and acidity (pI 3.7-4.0) and are active at a concentration that varies from 2.9 X 10(-12) to 1.2 X 10(-11) M. Data on amino acid composition revealed that an unusually high amount of cysteine (12-15.7%) and poor contents of basic amino acids are common to every pheromone. On the basis of this uniformity in the main biochemical traits, which also holds for the previously purified pheromone Er-1, it was concluded that E. raikovi mating pheromones are members of a family of proteins structurally diversified from each other to varying extents.
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Affiliation(s)
- S Raffioni
- Department of Cell Biology, University of Camerino, Italy
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A mutation ofEuplotes vannus causing induction of intraclonal conjugation (selfing) in low [K+]o. Cell Mol Life Sci 1987. [DOI: 10.1007/bf01951674] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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