Chromosome size and number polymorphisms in Leishmania infantum suggest amplification/deletion and possible genetic exchange

Pagès, Michel; Bastien, Patrick; Veas, Francisco; Rossi, Valérie; Bellis, Michel; Wincker, Patrick; Rioux, J. A.; Roizès, Gérard

doi:10.1016/0166-6851(89)90188-6

Cited by 69 publications

(35 citation statements)

References 26 publications

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“…By contrast, chromosome gain or loss (aneuploidy) in multicellular eukaryotes is either lethal or results in severe abnormalities, for example trisomy of chromosome 21 in humans with Down syndrome [6]. Despite the predominantly negative effects of aneuploidy, supernumerary chromosomes have been reported in tumor cells, yeast, and recently the protozoan Leishmania [7][8][9][10][11].…”

Section: The Flexible Genomes Of Leishmaniamentioning

confidence: 99%

“…homologous chromosomes are highly polymorphic [7,[21][22][23][24]. This size variation is probably the result of DNA amplification and deletion events, mainly in the subtelomeric repeat regions [7,25].…”

Section: The Flexible Genomes Of Leishmaniamentioning

confidence: 99%

“…This size variation is probably the result of DNA amplification and deletion events, mainly in the subtelomeric repeat regions [7,25]. Although Leishmania is considered to be a diploid organism, supporting evidence is not abundant [22].…”

Section: The Flexible Genomes Of Leishmaniamentioning

confidence: 99%

“…Since the errant karyotypes were first discovered, it was suspected that aneuploidy occurred in natural Leishmania strains; differences in karyotype have been found in L. infantum isolates and derived clones [7,22]. The number of homologous chromosomes is also polymorphic.…”

Section: Aneuploidy In Natural Leishmania Populationsmentioning

confidence: 99%

See 3 more Smart Citations

Adaptive mechanisms in pathogens: universal aneuploidy in Leishmania

Mannaert

Downing

Imamura

et al. 2012

Trends in Parasitology

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Section: The Flexible Genomes Of Leishmaniamentioning

confidence: 99%

Section: The Flexible Genomes Of Leishmaniamentioning

confidence: 99%

Section: The Flexible Genomes Of Leishmaniamentioning

confidence: 99%

Section: Aneuploidy In Natural Leishmania Populationsmentioning

confidence: 99%

See 2 more Smart Citations

Adaptive mechanisms in pathogens: universal aneuploidy in Leishmania

Mannaert

Downing

Imamura

et al. 2012

Trends in Parasitology

128

102

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“…However, the refinement of pulsed field gel electrophoresis (PFGE) methods over the last 10 years has enabled a molecular ''karyotype'' for the various Leishmania species to be obtained (Samaras and Spithill 1987;Pagès et al 1989;Bastien et al 1992 studies, by the use of 244 probe loci, enabled 36 physical linkage groups to be defined, and a genome size of ∼35 Mb to be calculated (Wincker et al 1996). Importantly, the physical linkage groups exhibited conservation among the Old World species of Leishmania, suggesting that overall chromosomal structure and gene order might have been maintained despite speciation and concomitant chromosome size variability (Wincker et al 1997).…”

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confidence: 99%

A Physical Map of the Leishmania majorFriedlin Genome

Ivens¹,

Lewis²,

Bagherzadeh³

et al. 1998

Genome Res.

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An extensive physical map of the Leishmania major Friedlin genome has been assembled by the combination of fingerprint analysis of a shuttle vector cosmid library and probe hybridization. The integrated data obtained for 9004 fingerprinted clones and 974 probes have placed 91.2% of the 33.58-Mb genome into contigs representing each of the 36 chromosomes. This first-generation map has already provided a suitable framework for both high-throughput DNA sequencing and functional studies of the L. major parasite.Leishmania is a flagellated protozoan parasite belonging to the family Trypanosomatidae. The 13 different species of Leishmania are responsible for a wide spectrum of human disease occurring mostly in the tropics and subtropics, although cases in North America have been documented (McHugh et al. 1996). Found in parts of Asia, the Mediterranean region, and South America, there are estimated to be over 2 million new cases of leishmaniasis each year in 88 countries, with 367 million people at risk (WHO 1995). Leishmaniasis thus constitutes a major threat to human health.The parasite is digenic; the extracellular, flagellated forms of Leishmania major differentiate from noninfective promastigotes to infective metacyclics in the alimentary tract of their dipteran (sandfly) vector. After inoculation into the mammalian host, the parasites become intracellular, entering macrophages and differentiating into nonmotile amastigotes. Infective parasites are able to resist the action of resident hydrolytic enzymes, inhibit activation of the oxidative burst, and mitigate the immunological attack of the host (Bard 1989;Killick-Kendrick 1990;Blackwell 1996;Mauel 1996). As a result, there is considerable worldwide interest in determining the factors that contribute to Leishmania's efficiency as a parasite.As a eukaryote, Leishmania is atypical. Genes are often organized in tandem repeats, many of which are transcribed polycistronically. Nonrepeated genes of related function can also occur in long transcription units, akin to operons in prokaryotes.Extensive post-transcriptional processing is then required to yield mature mRNAs, including the transsplicing of a 39-nucleotide spliced leader (SL, or miniexon-derived) RNA onto the 5Ј ends of all mRNA molecules (Miller et al. 1986;Ramamoorthy et al. 1996). In contrast, no introns have been detected, removing a requirement for cis splicing. Hence, Leishmania species are the subject of fundamental interest with respect to the evolution of gene regulatory mechanisms, as well as for the exploitation of these properties for the development of new methods of control.The application of standard genetic techniques to the study of Leishmania has been hampered by two factors: (1) No sexual cycle has been observed; and (2) the chromosomes do not condense at any phase of the cell cycle. However, the refinement of pulsed field gel electrophoresis (PFGE) methods over the last 10 years has enabled a molecular ''karyotype'' for the various Leishmania species to be obtained (Samaras and Spithill 19...

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Autonomously replicating single-copy episomes in Trypanosoma brucei show unusual stability.

1993

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We have obtained several autonomously replicating plasmids in procyclic Trypanosoma brucei. Two of these have been analyzed in detail. Both exist as monomeric single‐copy episomes, which nevertheless demonstrate significant stability. These episomes transform procyclics at frequencies that are at least 60‐fold higher than those achieved earlier with non‐replicating molecules. A modified version of one of these episomes is able to replicate autonomously in bloodstream form T. brucei but it is unstable in this developmental stage of the organism. These episomes will prove useful as shuttle vectors, in functional complementation studies, in the construction of promoter‐traps for the isolation of transcriptional promoters in T. brucei, and importantly, as models for the analysis of DNA replication in this ancient eukaryotic lineage.

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Chromosome size and number polymorphisms in Leishmania infantum suggest amplification/deletion and possible genetic exchange

Cited by 69 publications

References 26 publications

Adaptive mechanisms in pathogens: universal aneuploidy in Leishmania

Adaptive mechanisms in pathogens: universal aneuploidy in Leishmania

A Physical Map of the Leishmania majorFriedlin Genome

Autonomously replicating single-copy episomes in Trypanosoma brucei show unusual stability.

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