Identification of the telomere in Trypanosoma cruzi reveals highly heterogeneous telomere lengths in different parasite strains

Freitas‐Junior, Lúcio H.; Porto, Rafael Marques; Pirrit, Lindsay A.; Schenkman, Sérgio; Scherf, Artur

doi:10.1093/nar/27.12.2451

Cited by 26 publications

(22 citation statements)

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“…This is the most extensive analysis of telomere length in different T. brucei isolates. Telomeres in different T. cruzi isolates vary in size from 1-10 kB (Freitas-Junior, et al, 1999). More recently, telomere length was monitored during growth of Leishmania major, L. tarentolae and Crithidia fasciculata (Genest and Borst, 2007).…”

Section: Discussionmentioning

confidence: 99%

Telomere length in Trypanosoma brucei

Dreesen

Cross

2008

Experimental Parasitology

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Trypanosoma brucei-thwarts the host immune response by replacing its variant surface glycoprotein (VSG). The actively transcribed VSG is located in one of ~20 telomeric expression sites (ES). Antigenic variation can occur by transcriptional switching, reciprocal translocations, or duplicative gene conversion events among ES or with the large repertoire of telomeric and nontelomeric VSG. In recently isolated strains, duplicative gene conversion occurs at a high frequency and predominates, but the switching frequency decreases dramatically upon laboratory-adaptation. Uniquely, T. brucei telomeres grow-apparently indefinitely-at a steady rate of 6-12 base pairs (bp) per population doubling (PD), but the telomere adjacent to an active ES undergoes frequent truncations. Using two-dimensional gel electrophoresis, we demonstrate that all of the chromosome classes of fast-switching and minimally propagated T. brucei have shorter telomeres than extensively propagated Lister 427 clones, suggesting a link between laboratory adaptation, telomere growth, and VSG switching rates.

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Section: Discussionmentioning

confidence: 99%

Telomere length in Trypanosoma brucei

Dreesen

Cross

2008

Experimental Parasitology

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“…TRF heterogeneity has also been reported for T. cruzi (Freitas-Junior et al 1999;Chiurillo et al 1999), as well as for Leishmania and T. brucei (Fu and Barker 1998; Chiurillo et al 2000;El-Sayed et al 2005;Conte and Cano 2005). This fact might be explained by variation in the number of telomeric hexamer repeats or by the presence of sequence polymorphisms that create or destroy restriction sites for the endonucleases used (Freitas-Junior et al 1999;Vargas et al 2004).…”

Section: Discussionmentioning

confidence: 94%

“…Eukaryotic telomeres share characteristic features such as the same 5′-TTAGGG-3′ sequence found in all trypanosomatids and most vertebrates and the heterogeneity in terminal restriction fragments (TRFs) between chromosomes of the same cell and between species (Wincker et al 1996;Freitas-Junior et al 1999;Conte and Cano 2005;Chiurillo et al 2000;El-Sayed et al 2005;Lira et al 2007). Analysis of telomeric and subtelomeric regions has contributed to the understanding of the biology of different trypanosomatid species.…”

Section: Introductionmentioning

confidence: 99%

“…Analysis of telomeric and subtelomeric regions has contributed to the understanding of the biology of different trypanosomatid species. The subtelomeric regions contain genes that encode proteins related to the virulence and escape mechanisms of these parasites, such as the gp85 and gp90 proteins of T. cruzi (Freitas-Junior et al 1999;Chiurillo et al 1999Chiurillo et al , 2002 and the variable surface glycoproteins of Trypanosoma brucei (Borst and Rudenko 1994;Vanhamme et al 2001). In addition, the subtelomeric regions of T. cruzi, T. brucei, and Leishmania major contain specific sequences that can be used as molecular markers (Fu and Barker 1998;Chiurillo et al 2000Chiurillo et al , 2001Chiurillo et al , 2002El-Sayed et al 2005).…”

Section: Introductionmentioning

confidence: 99%

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Sequencing and analysis of chromosomal extremities of Trypanosoma rangeli in comparison with Trypanosoma cruzi lineages

et al. 2010

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The aim of this study was to investigate the genetic variability of sequences present in the chromosome ends of Trypanosoma rangeli strains defined by the presence (+) or absence (-) of KP1 minicircles, and to compare the mean terminal restriction fragment (TRF) lengths to those of Trypanosoma cruzi populations representative of groups TcI, TcII, TcIV, and TcVI. Southern blots containing RsaI-digested genomic DNA of T. rangeli KP1(+) strains, T. rangeli KP1(-) strains, and T. cruzi strains were probed with the previously described subtelomeric sequences (170 bp) of T. rangeli and with telomeric hexamer repeats. Mean TRF length analysis showed that the chromosome ends of T. rangeli are distinctly organized, with TRFs ranging from 1.3 to 9 kb for KP1(+) strains and from 0.3 to 5.0 kb for KP1(-) strains. In T. cruzi, TRF length ranged from 0.2 to 9 kb and no association with the genotype of the parasite could be established. Sequence analysis of the 170-bp amplicons revealed the occurrence of sequence polymorphisms in the subtelomeric region between and within KP1(+) and KP1(-) strains. The GTT triplet was detected in all KP1(+) strains, except for strain Cas4, but not in any of the KP1(-) strains. The dendrogram constructed by alignment of all T. rangeli strains showed the division into two main groups, mainly related to the presence or absence of the KP1 minicircle. In conclusion, the present results extend the genotype differences demonstrated by kDNA and karyotype analysis in T. rangeli to the chromosome ends of the parasite.

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“…Generally, the central core of protozoan chromosomes remains stable while the subtelomeric regions vary. Variability in these regions is responsible for a major part of the large polymorphisms observed between chromosome homologues in parasitic protozoa (72,73,113,129,179). Because of this variability, DNA elements positioned at chromosomal margins are apt to live short lives unless they can expand rapidly enough to offset the high rate of casualties.…”

Section: Life On the Edge: Subtelomeric Repeatsmentioning

confidence: 99%

Repetitive Elements in Genomes of Parasitic Protozoa

Wickstead

Ersfeld

Gull

2003

Microbiol Mol Biol Rev

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Repetitive DNA elements have been a part of the genomic fauna of eukaryotes perhaps since their very beginnings. Millions of years of coevolution have given repeats central roles in chromosome maintenance and genetic modulation. Here we review the genomes of parasitic protozoa in the context of the current understanding of repetitive elements. Particular reference is made to repeats in five medically important species with ongoing or completed genome sequencing projects: Plasmodium falciparum, Leishmania major, Trypanosoma brucei, Trypanosoma cruzi, and Giardia lamblia. These organisms are used to illustrate five thematic classes of repeats with different structures and genomic locations. We discuss how these repeat classes may interact with parasitic life-style and also how they can be used as experimental tools. The story which emerges is one of opportunism and upheaval which have been employed to add genetic diversity and genomic flexibility

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Identification of the telomere in Trypanosoma cruzi reveals highly heterogeneous telomere lengths in different parasite strains

Cited by 26 publications

References 4 publications

Telomere length in Trypanosoma brucei

Telomere length in Trypanosoma brucei

Sequencing and analysis of chromosomal extremities of Trypanosoma rangeli in comparison with Trypanosoma cruzi lineages

Repetitive Elements in Genomes of Parasitic Protozoa

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