Analysis of Expressed Sequence Tags (ESTs) in the Ciliated Protozoan <i>Tetrahymena thermophila</i>

Fillingham, Jeffrey; Chilcoat, N. Doane; Turkewitz, Aaron P.; Orias, Eduardo; Reith, Michael; Pearlman, Ronald E.

doi:10.1111/j.1550-7408.2002.tb00350.x

Cited by 31 publications

(28 citation statements)

References 63 publications

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“…It will be of interest to determine whether REP elements are capable of transposition during vegetative growth. We have previously identified a growth-associated piwi-related gene in an expressed sequence tag sequencing project (20). Caenorhabditis elegans mutants carrying mutations in the piwirelated gene rde-1 exhibit transposon mobilization (51).…”

Section: Discussionmentioning

confidence: 99%

A Non-Long Terminal Repeat Retrotransposon Family Is Restricted to the Germ Line Micronucleus of the Ciliated Protozoan Tetrahymena thermophila

et al. 2004

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The ciliated protozoan Tetrahymena thermophila undergoes extensive programmed DNA rearrangements during the development of a somatic macronucleus from the germ line micronucleus in its sexual cycle. To investigate the relationship between programmed DNA rearrangements and transposable elements, we identified several members of a family of non-long terminal repeat (LTR) retrotransposons (retroposons) in T. thermophila, the first characterized in the ciliated protozoa. This multiple-copy retrotransposon family is restricted to the micronucleus of T. thermophila. The REP (Tetrahymena non-LTR retroposon) elements encode an ORF2 typical of non-LTR elements that contains apurinic/apyrimidinic endonuclease (APE) and reverse transcriptase (RT) domains. Phylogenetic analysis of the RT and APE domains indicates that the element forms a deep-branching clade within the non-LTR retrotransposon family. Northern analysis with a probe to the conserved RT domain indicates that transcripts from the element are small and heterogeneous in length during early macronuclear development. The presence of a repeated transposable element in the genome is consistent with the model that programmed DNA deletion in T. thermophila evolved as a method of eliminating deleterious transposons from the somatic macronucleus.Developmentally programmed DNA rearrangements occur in a wide variety of organisms (reviewed in reference 5). Functions such as altering gene dosage or directly regulating gene expression have been assigned to many but not all examples of programmed DNA rearrangements. A clinically important example of a programmed DNA rearrangement is V(D)J recombination (2). In addition, a variety of mammalian parasites use programmed DNA rearrangements to vary their surface antigens to avoid host immune response (4). The function of other programmed DNA rearrangements is not as clear. The extensive genome rearrangements that occur during nuclear development in the ciliated protozoa provide an example of programmed DNA rearrangements with poorly understood function.Like all ciliated protozoa, the oligohymenopheran Tetrahymena thermophila displays nuclear dimorphism with a mostly transcriptionally silent diploid germ line nucleus (micronucleus) and a polyploid and transcriptionally active somatic nucleus (macronucleus) within the same cell. The macronucleus develops from a mitotic product of the micronucleus during conjugation. When two cells of different mating types conjugate, the micronucleus in each divides meiotically and mitotically to generate a haploid gametic nucleus that is reciprocally exchanged and fuses with that of its partner to form a zygotic nucleus. This zygotic nucleus divides and from one of the products develops a new macronucleus, while the old macronucleus is concurrently degraded. In T. thermophila, macronuclear development involves extensive programmed DNA rearrangements, including chromosome fragmentation, DNA amplification, and site-specific interstitial DNA deletion (12). Interstitial DNA deletion is responsible for t...

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Section: Discussionmentioning

confidence: 99%

A Non-Long Terminal Repeat Retrotransposon Family Is Restricted to the Germ Line Micronucleus of the Ciliated Protozoan Tetrahymena thermophila

et al. 2004

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“…The N-terminal sequence of the purified protein (Pgp1p) exactly matched residues 22 to 40 of a predicted protein encoded by a cDNA from a Tetrahymena expressed sequence tag cDNA library (12). The full-length sequence of PGP1 was obtained by 5Ј and 3Ј rapid amplification of cDNA ends (36).…”

Section: Methodsmentioning

confidence: 99%

Endoplasmic Reticulum Retention Signal-Dependent Glycylation of the Hsp70/Grp170-Related Pgp1p in Tetrahymena

2007

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Glycylation is an uncommon posttranslational modification. It has been found that tubulin glycylation is essential for cell survival in Tetrahymena. Here we describe PGP1, a Tetrahymena gene encoding an Hsp70 homologue that is a novel glycylated protein. Pgp1p is a conserved glycoprotein that localizes within the lumen of the endoplasmic reticulum (ER). We demonstrate that PGP1 is essential for viability and present evidence that both glycosylation and ER retention are necessary but not sufficient for glycylation.

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“…To date, research using T. thermophila has made great contributions to fundamental biological discoveries such as dynein [8], catalytic RNA [9], telomeric repeats [10,11], telomerase [12], the function of histone acetylation [13], and RNAi mechanisms in macronucleus reprogramming [14]. Analysis of expressed sequence tags in the genome of Tetrahymena has demonstrated that it has a high degree of functional homology with human and mammalian genomes [15]. The organism also shares many core processes with a wide variety of eukaryotes (including humans) [16] that are not found in other single-celled model systems (e.g., yeast).…”

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Toxicogenomic investigation of Tetrahymena thermophila exposed to dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Chang

Feng

Miao

2011

Sci. China Life Sci.

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Dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are persistent in the environment and cause continuous toxic effects in humans and aquatic life. Tetrahymena thermophila has the potential for use as a model for research regarding toxicants. In this study, this organism was used to analyze a genome-wide microarray generated from cells exposed to DDT, TBT and TCDD. To accomplish this, genes differentially expressed when treated with each toxicant were identified, after which their functions were categorized using GO enrichment analysis. The results suggested that the responses of T. thermophila were similar to those of multicellular organisms. Additionally, the context likelihood of relatedness method (CLR) was applied to construct a TCDD-relevant network. The T-shaped network obtained could be functionally divided into two subnetworks. The general functions of both subnetworks were related to the epigenetic mechanism of TCDD. Based on analysis of the networks, a model of the TCDD effect on T. thermophila was inferred. Thus, Tetrahymena has the potential to be a good unicellular eukaryotic model for toxic mechanism research at the genome level. microarray, enrichment analysis, gene interaction network, pollutant Citation:Chang Y, Feng L F, Miao W. Toxicogenomic investigation of Tetrahymena thermophila exposed to dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Sci China Life Sci, 2011, 54: 617 -625,

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Analysis of Expressed Sequence Tags (ESTs) in the Ciliated Protozoan Tetrahymena thermophila

Cited by 31 publications

References 63 publications

A Non-Long Terminal Repeat Retrotransposon Family Is Restricted to the Germ Line Micronucleus of the Ciliated Protozoan Tetrahymena thermophila

A Non-Long Terminal Repeat Retrotransposon Family Is Restricted to the Germ Line Micronucleus of the Ciliated Protozoan Tetrahymena thermophila

Endoplasmic Reticulum Retention Signal-Dependent Glycylation of the Hsp70/Grp170-Related Pgp1p in Tetrahymena

Toxicogenomic investigation of Tetrahymena thermophila exposed to dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

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