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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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Karyotype polymorphism between the G strain and clone D11.Panel A) Chromosomal bands were separated by Pulsed-Field Gel Electrophoresis (PFGE) and stained with SYBR Green I. The bands from the G strain were numbered using Arabic numerals (1–19) as in a previous study (Souza et al., 2011) while capital letters (A – U) were used for clone D11, starting from the smallest band. Panel B) Diagrammatic representation of the molecular karyotypes of the G strain and clone D11. The rectangles represent a unique distinguishable band visualized after SYBR Green I staining. The thickness of the rectangles represents the proportional staining of each chromosomal band. The number and letter of chromosomal bands as well as their molecular weight are indicated to the left and right of each strip, respectively.
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pone-0063738-g001: Karyotype polymorphism between the G strain and clone D11.Panel A) Chromosomal bands were separated by Pulsed-Field Gel Electrophoresis (PFGE) and stained with SYBR Green I. The bands from the G strain were numbered using Arabic numerals (1–19) as in a previous study (Souza et al., 2011) while capital letters (A – U) were used for clone D11, starting from the smallest band. Panel B) Diagrammatic representation of the molecular karyotypes of the G strain and clone D11. The rectangles represent a unique distinguishable band visualized after SYBR Green I staining. The thickness of the rectangles represents the proportional staining of each chromosomal band. The number and letter of chromosomal bands as well as their molecular weight are indicated to the left and right of each strip, respectively.

Mentions: The chromosomal bands of the G strain and clone D11 were separated by PFGE and stained with EtBr (Figure 1). We refer to a DNA band visible on PFGE after staining with EtBr as a “chromosomal band”. This can contain one, two or more, not necessarily homologous, co-migrating chromosomes. EtBr staining pattern and the diagrammatic representation of chromosomal bands from the G strain and clone D11 are shown in Figures 1A and 1B, respectively. We identified 19 and 21 non-stoichiometrically staining chromosomal bands in the G strain and clone D11, respectively, by scanning pulsed-field gels stained with SYBR Green I. The molecular karyotype of the G strain is composed of 19 chromosomal bands: 11 megabase bands ranging from 2.83 to 1.08 Mb and 8 intermediate bands between 0.96 and 0.53 Mb.


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)

Karyotype polymorphism between the G strain and clone D11.Panel A) Chromosomal bands were separated by Pulsed-Field Gel Electrophoresis (PFGE) and stained with SYBR Green I. The bands from the G strain were numbered using Arabic numerals (1–19) as in a previous study (Souza et al., 2011) while capital letters (A – U) were used for clone D11, starting from the smallest band. Panel B) Diagrammatic representation of the molecular karyotypes of the G strain and clone D11. The rectangles represent a unique distinguishable band visualized after SYBR Green I staining. The thickness of the rectangles represents the proportional staining of each chromosomal band. The number and letter of chromosomal bands as well as their molecular weight are indicated to the left and right of each strip, respectively.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0063738-g001: Karyotype polymorphism between the G strain and clone D11.Panel A) Chromosomal bands were separated by Pulsed-Field Gel Electrophoresis (PFGE) and stained with SYBR Green I. The bands from the G strain were numbered using Arabic numerals (1–19) as in a previous study (Souza et al., 2011) while capital letters (A – U) were used for clone D11, starting from the smallest band. Panel B) Diagrammatic representation of the molecular karyotypes of the G strain and clone D11. The rectangles represent a unique distinguishable band visualized after SYBR Green I staining. The thickness of the rectangles represents the proportional staining of each chromosomal band. The number and letter of chromosomal bands as well as their molecular weight are indicated to the left and right of each strip, respectively.
Mentions: The chromosomal bands of the G strain and clone D11 were separated by PFGE and stained with EtBr (Figure 1). We refer to a DNA band visible on PFGE after staining with EtBr as a “chromosomal band”. This can contain one, two or more, not necessarily homologous, co-migrating chromosomes. EtBr staining pattern and the diagrammatic representation of chromosomal bands from the G strain and clone D11 are shown in Figures 1A and 1B, respectively. We identified 19 and 21 non-stoichiometrically staining chromosomal bands in the G strain and clone D11, respectively, by scanning pulsed-field gels stained with SYBR Green I. The molecular karyotype of the G strain is composed of 19 chromosomal bands: 11 megabase bands ranging from 2.83 to 1.08 Mb and 8 intermediate bands between 0.96 and 0.53 Mb.

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