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Interclonal variations in the molecular karyotype of Trypanosoma cruzi: chromosome rearrangements in a single cell-derived clone of the G strain.

Lima FM, Souza RT, Santori FR, Santos MF, Cortez DR, Barros RM, Cano MI, Valadares HM, Macedo AM, Mortara RA, da Silveira JF - PLoS ONE (2013)

Bottom Line: Our results also suggest that telomeric regions are involved in this process.The variant represented by clone D11 could have been induced by the stress of the cloning procedure or could, as has been suggested for Leishmania infantum, have emerged from a multiclonal, mosaic parasite population submitted to frequent DNA amplification/deletion events, leading to a 'mosaic' structure with different individuals having differently sized versions of the same chromosomes.If this is the case, the variant represented by clone D11 would be better adapted to survive the stress induced by cloning, which includes intracellular development in the mammalian cell.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil.

ABSTRACT
Trypanosoma cruzi comprises a pool of populations which are genetically diverse in terms of DNA content, growth and infectivity. Inter- and intra-strain karyotype heterogeneities have been reported, suggesting that chromosomal rearrangements occurred during the evolution of this parasite. Clone D11 is a single-cell-derived clone of the T. cruzi G strain selected by the minimal dilution method and by infecting Vero cells with metacyclic trypomastigotes. Here we report that the karyotype of clone D11 differs from that of the G strain in both number and size of chromosomal bands. Large chromosomal rearrangement was observed in the chromosomes carrying the tubulin loci. However, most of the chromosome length polymorphisms were of small amplitude, and the absence of one band in clone D11 in relation to its reference position in the G strain could be correlated to the presence of a novel band migrating above or below this position. Despite the presence of chromosomal polymorphism, large syntenic groups were conserved between the isolates. The appearance of new chromosomal bands in clone D11 could be explained by chromosome fusion followed by a chromosome break or interchromosomal exchange of large DNA segments. Our results also suggest that telomeric regions are involved in this process. The variant represented by clone D11 could have been induced by the stress of the cloning procedure or could, as has been suggested for Leishmania infantum, have emerged from a multiclonal, mosaic parasite population submitted to frequent DNA amplification/deletion events, leading to a 'mosaic' structure with different individuals having differently sized versions of the same chromosomes. If this is the case, the variant represented by clone D11 would be better adapted to survive the stress induced by cloning, which includes intracellular development in the mammalian cell. Karyotype polymorphism could be part of the T. cruzi arsenal for responding to environmental pressure.

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Identification of homologous chromosomal bands of similar molecular sizes in the G strain and clone D11.Hybridization profile of specific chromosomal markers hybridized to one or more bands of similar molecular size in both isolates after chromosome separation by PFGE and Southern-blot hybridization. The markers used are TEUF0099, rDNA18S, TEUF0242 and ADC. Gene identification and GenBank accession number of each marker are shown in Table 1.
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pone-0063738-g002: Identification of homologous chromosomal bands of similar molecular sizes in the G strain and clone D11.Hybridization profile of specific chromosomal markers hybridized to one or more bands of similar molecular size in both isolates after chromosome separation by PFGE and Southern-blot hybridization. The markers used are TEUF0099, rDNA18S, TEUF0242 and ADC. Gene identification and GenBank accession number of each marker are shown in Table 1.

Mentions: To investigate variations in chromosome size, Southern blots were carried out and chromosomes that had been separated by PFGE were hybridized with a panel of cloned sequences (Table 1), including proteins and genes encoding ribosomal RNA, chromosome specific-markers and polymorphic repetitive sequences. The overall analysis showed distinct hybridization patterns represented by markers that hybridize to (i) one or more very similar-sized bands in both isolates (Figures 2 and 3); (ii) one band in the G strain and two bands in clone D11 or vice versa, with differences in size of up to 330 kb (Figure 4); and (iii) many bands generating a complex hybridization pattern (Figure S2).


Interclonal variations in the molecular karyotype of Trypanosoma cruzi: chromosome rearrangements in a single cell-derived clone of the G strain.

Lima FM, Souza RT, Santori FR, Santos MF, Cortez DR, Barros RM, Cano MI, Valadares HM, Macedo AM, Mortara RA, da Silveira JF - PLoS ONE (2013)

Identification of homologous chromosomal bands of similar molecular sizes in the G strain and clone D11.Hybridization profile of specific chromosomal markers hybridized to one or more bands of similar molecular size in both isolates after chromosome separation by PFGE and Southern-blot hybridization. The markers used are TEUF0099, rDNA18S, TEUF0242 and ADC. Gene identification and GenBank accession number of each marker are shown in Table 1.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646811&req=5

pone-0063738-g002: Identification of homologous chromosomal bands of similar molecular sizes in the G strain and clone D11.Hybridization profile of specific chromosomal markers hybridized to one or more bands of similar molecular size in both isolates after chromosome separation by PFGE and Southern-blot hybridization. The markers used are TEUF0099, rDNA18S, TEUF0242 and ADC. Gene identification and GenBank accession number of each marker are shown in Table 1.
Mentions: To investigate variations in chromosome size, Southern blots were carried out and chromosomes that had been separated by PFGE were hybridized with a panel of cloned sequences (Table 1), including proteins and genes encoding ribosomal RNA, chromosome specific-markers and polymorphic repetitive sequences. The overall analysis showed distinct hybridization patterns represented by markers that hybridize to (i) one or more very similar-sized bands in both isolates (Figures 2 and 3); (ii) one band in the G strain and two bands in clone D11 or vice versa, with differences in size of up to 330 kb (Figure 4); and (iii) many bands generating a complex hybridization pattern (Figure S2).

Bottom Line: Our results also suggest that telomeric regions are involved in this process.The variant represented by clone D11 could have been induced by the stress of the cloning procedure or could, as has been suggested for Leishmania infantum, have emerged from a multiclonal, mosaic parasite population submitted to frequent DNA amplification/deletion events, leading to a 'mosaic' structure with different individuals having differently sized versions of the same chromosomes.If this is the case, the variant represented by clone D11 would be better adapted to survive the stress induced by cloning, which includes intracellular development in the mammalian cell.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil.

ABSTRACT
Trypanosoma cruzi comprises a pool of populations which are genetically diverse in terms of DNA content, growth and infectivity. Inter- and intra-strain karyotype heterogeneities have been reported, suggesting that chromosomal rearrangements occurred during the evolution of this parasite. Clone D11 is a single-cell-derived clone of the T. cruzi G strain selected by the minimal dilution method and by infecting Vero cells with metacyclic trypomastigotes. Here we report that the karyotype of clone D11 differs from that of the G strain in both number and size of chromosomal bands. Large chromosomal rearrangement was observed in the chromosomes carrying the tubulin loci. However, most of the chromosome length polymorphisms were of small amplitude, and the absence of one band in clone D11 in relation to its reference position in the G strain could be correlated to the presence of a novel band migrating above or below this position. Despite the presence of chromosomal polymorphism, large syntenic groups were conserved between the isolates. The appearance of new chromosomal bands in clone D11 could be explained by chromosome fusion followed by a chromosome break or interchromosomal exchange of large DNA segments. Our results also suggest that telomeric regions are involved in this process. The variant represented by clone D11 could have been induced by the stress of the cloning procedure or could, as has been suggested for Leishmania infantum, have emerged from a multiclonal, mosaic parasite population submitted to frequent DNA amplification/deletion events, leading to a 'mosaic' structure with different individuals having differently sized versions of the same chromosomes. If this is the case, the variant represented by clone D11 would be better adapted to survive the stress induced by cloning, which includes intracellular development in the mammalian cell. Karyotype polymorphism could be part of the T. cruzi arsenal for responding to environmental pressure.

Show MeSH
Related in: MedlinePlus