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Genomic analyses, gene expression and antigenic profile of the trans-sialidase superfamily of Trypanosoma cruzi reveal an undetected level of complexity.

Freitas LM, dos Santos SL, Rodrigues-Luiz GF, Mendes TA, Rodrigues TS, Gazzinelli RT, Teixeira SM, Fujiwara RT, Bartholomeu DC - PLoS ONE (2011)

Bottom Line: We demonstrated that all seven groups represented in the array are antigenic.A highly reactive peptide occurs in sixty TcS proteins including members of two new groups and may contribute to the known cross-reactivity of T. cruzi epitopes during infection.Taken together, our results contribute to a better understanding of the real complexity of the TcS family and open new avenues for investigating novel roles of this family during T. cruzi infection.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.

ABSTRACT
The protozoan parasite Trypanosoma cruzi is the etiologic agent of Chagas disease, a highly debilitating human pathology that affects millions of people in the Americas. The sequencing of this parasite's genome reveals that trans-sialidase/trans-sialidase-like (TcS), a polymorphic protein family known to be involved in several aspects of T. cruzi biology, is the largest T. cruzi gene family, encoding more than 1,400 genes. Despite the fact that four TcS groups are well characterized and only one of the groups contains active trans-sialidases, all members of the family are annotated in the T. cruzi genome database as trans-sialidase. After performing sequence clustering analysis with all TcS complete genes, we identified four additional groups, demonstrating that the TcS family is even more heterogeneous than previously thought. Interestingly, members of distinct TcS groups show distinctive patterns of chromosome localization. Members of the TcSgroupII, which harbor proteins involved in host cell attachment/invasion, are preferentially located in subtelomeric regions, whereas members of the largest and new TcSgroupV have internal chromosomal locations. Real-time RT-PCR confirms the expression of genes derived from new groups and shows that the pattern of expression is not similar within and between groups. We also performed B-cell epitope prediction on the family and constructed a TcS specific peptide array, which was screened with sera from T. cruzi-infected mice. We demonstrated that all seven groups represented in the array are antigenic. A highly reactive peptide occurs in sixty TcS proteins including members of two new groups and may contribute to the known cross-reactivity of T. cruzi epitopes during infection. Taken together, our results contribute to a better understanding of the real complexity of the TcS family and open new avenues for investigating novel roles of this family during T. cruzi infection.

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Related in: MedlinePlus

Multidimensional scaling (MDS) plot of the 3′ flanking regions of the TcS genes.A total of 300 nucleotides downstream from the stop codon of each gene were analyzed. Sequences smaller than 300 nucleotides were excluded. Previously characterized genes were mapped on the MDS.
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pone-0025914-g006: Multidimensional scaling (MDS) plot of the 3′ flanking regions of the TcS genes.A total of 300 nucleotides downstream from the stop codon of each gene were analyzed. Sequences smaller than 300 nucleotides were excluded. Previously characterized genes were mapped on the MDS.

Mentions: It is well established that, in Trypanosomatids, the 3′UTR regions are involved in post-transcriptional control mechanisms that confer stage-specific gene expression. To investigate whether the 3′ flanking sequences of TcS genes that belong to the same groups are conserved, we performed pairwise alignments of the 300 nt downstream of the stop codon of the TcSs, and the distance matrix was used to generate the MDS projection. We decided to analyze 300 nt downstream from the stop codon because this is the mean average length of the T. cruzi 3′UTRs [32]. The sequences were then color-coded according to the protein clusters showed in Figure 1. TcS genes already characterized as well as those genes whose expression levels were analyzed by real-time RT-PCR (Figure 5) were then mapped onto the MDS projection (Figure 6). We could not find a very clear association between the protein and the 3′ flanking region distances. For example, members of the TcSgroupV (red) form a robust cluster at the protein level and are much more variable according to the analysis of the 3′ flanking region. Also, the 3′ flanking regions of TcSgroupII (dark green) members are scattered in three MDS areas. On the other hand, the 3′ flanking regions of the TcSgroupVIII (purple) members clustered together, which suggests that similar mechanisms may control the expression of some of their genes. Interestingly, the 3′ flanking regions of SAPA and TCNA, both active trans-sialidase enzymes expressed in the trypomastigote forms (TcSgroupI), are clustered very close. Also, the 3′ flanking region of the TS-epi, an active trans-sialidase that is expressed in the epimastigote stage that also belongs to TcSgroupI, is located farther away from the SAPA and TCNA sequences. Moreover, the 3′ flanking region of gp90 and gp82, both expressed in the metacyclic trypomastigotes, and ASP-2, expressed in the amastigote stage, all belong to TcSgroupII and are very close in the MDS projection. Interestingly, although Tc85-11_SA85-1.1 and TsTc13 are expressed in the trypomastigote stage, they are divergent at the protein level (Figure 1) and belong to different TcS groups (II and IV, respectively); they have similar 3′ flanking regions, which suggests that similar mechanisms for gene regulation may act on both genes.


Genomic analyses, gene expression and antigenic profile of the trans-sialidase superfamily of Trypanosoma cruzi reveal an undetected level of complexity.

Freitas LM, dos Santos SL, Rodrigues-Luiz GF, Mendes TA, Rodrigues TS, Gazzinelli RT, Teixeira SM, Fujiwara RT, Bartholomeu DC - PLoS ONE (2011)

Multidimensional scaling (MDS) plot of the 3′ flanking regions of the TcS genes.A total of 300 nucleotides downstream from the stop codon of each gene were analyzed. Sequences smaller than 300 nucleotides were excluded. Previously characterized genes were mapped on the MDS.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198458&req=5

pone-0025914-g006: Multidimensional scaling (MDS) plot of the 3′ flanking regions of the TcS genes.A total of 300 nucleotides downstream from the stop codon of each gene were analyzed. Sequences smaller than 300 nucleotides were excluded. Previously characterized genes were mapped on the MDS.
Mentions: It is well established that, in Trypanosomatids, the 3′UTR regions are involved in post-transcriptional control mechanisms that confer stage-specific gene expression. To investigate whether the 3′ flanking sequences of TcS genes that belong to the same groups are conserved, we performed pairwise alignments of the 300 nt downstream of the stop codon of the TcSs, and the distance matrix was used to generate the MDS projection. We decided to analyze 300 nt downstream from the stop codon because this is the mean average length of the T. cruzi 3′UTRs [32]. The sequences were then color-coded according to the protein clusters showed in Figure 1. TcS genes already characterized as well as those genes whose expression levels were analyzed by real-time RT-PCR (Figure 5) were then mapped onto the MDS projection (Figure 6). We could not find a very clear association between the protein and the 3′ flanking region distances. For example, members of the TcSgroupV (red) form a robust cluster at the protein level and are much more variable according to the analysis of the 3′ flanking region. Also, the 3′ flanking regions of TcSgroupII (dark green) members are scattered in three MDS areas. On the other hand, the 3′ flanking regions of the TcSgroupVIII (purple) members clustered together, which suggests that similar mechanisms may control the expression of some of their genes. Interestingly, the 3′ flanking regions of SAPA and TCNA, both active trans-sialidase enzymes expressed in the trypomastigote forms (TcSgroupI), are clustered very close. Also, the 3′ flanking region of the TS-epi, an active trans-sialidase that is expressed in the epimastigote stage that also belongs to TcSgroupI, is located farther away from the SAPA and TCNA sequences. Moreover, the 3′ flanking region of gp90 and gp82, both expressed in the metacyclic trypomastigotes, and ASP-2, expressed in the amastigote stage, all belong to TcSgroupII and are very close in the MDS projection. Interestingly, although Tc85-11_SA85-1.1 and TsTc13 are expressed in the trypomastigote stage, they are divergent at the protein level (Figure 1) and belong to different TcS groups (II and IV, respectively); they have similar 3′ flanking regions, which suggests that similar mechanisms for gene regulation may act on both genes.

Bottom Line: We demonstrated that all seven groups represented in the array are antigenic.A highly reactive peptide occurs in sixty TcS proteins including members of two new groups and may contribute to the known cross-reactivity of T. cruzi epitopes during infection.Taken together, our results contribute to a better understanding of the real complexity of the TcS family and open new avenues for investigating novel roles of this family during T. cruzi infection.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.

ABSTRACT
The protozoan parasite Trypanosoma cruzi is the etiologic agent of Chagas disease, a highly debilitating human pathology that affects millions of people in the Americas. The sequencing of this parasite's genome reveals that trans-sialidase/trans-sialidase-like (TcS), a polymorphic protein family known to be involved in several aspects of T. cruzi biology, is the largest T. cruzi gene family, encoding more than 1,400 genes. Despite the fact that four TcS groups are well characterized and only one of the groups contains active trans-sialidases, all members of the family are annotated in the T. cruzi genome database as trans-sialidase. After performing sequence clustering analysis with all TcS complete genes, we identified four additional groups, demonstrating that the TcS family is even more heterogeneous than previously thought. Interestingly, members of distinct TcS groups show distinctive patterns of chromosome localization. Members of the TcSgroupII, which harbor proteins involved in host cell attachment/invasion, are preferentially located in subtelomeric regions, whereas members of the largest and new TcSgroupV have internal chromosomal locations. Real-time RT-PCR confirms the expression of genes derived from new groups and shows that the pattern of expression is not similar within and between groups. We also performed B-cell epitope prediction on the family and constructed a TcS specific peptide array, which was screened with sera from T. cruzi-infected mice. We demonstrated that all seven groups represented in the array are antigenic. A highly reactive peptide occurs in sixty TcS proteins including members of two new groups and may contribute to the known cross-reactivity of T. cruzi epitopes during infection. Taken together, our results contribute to a better understanding of the real complexity of the TcS family and open new avenues for investigating novel roles of this family during T. cruzi infection.

Show MeSH
Related in: MedlinePlus