cruzi strains. Amastin amino acid sequences from CL Brener, Esmeraldo and Sylvio X-10 strains were used to generate a tree rooted with an α-amastin sequence from Crithidia sp. Bootstrap values followed by branch length are shown in the major basal nodes. In spite of the sequence divergence, an alignment of polypeptide sequences belonging to all amastin sub-families shows increased amino acid conservation within the putative hydrophobic click here transmembrane domains. Within the predicted extracellular domains, two highly conserved cysteine and one tryptophan residues, that are part of the 10 amino acid “amastin signature” [8], may be critical for amastin function (Additional file 1: Figure S1B). On the other hand, the more variable

sequences present in the two predicted extracellular, hydrophilic domains suggest that this portion of the protein, which, in amastigotes, are in contact with the host cell cytoplasm, may interact with distinct

host cell proteins. Because the assembly of CL Brener genome does not include its complete sequence, we conducted a read-based analysis to estimate the total number of amastin genes in this strain of the parasite. It is well known that the assembly of the CL Brener genome is only accurate for non-repetitive regions, and this website for tandemly repeated genes, misassembles frequently occurred since most repetitive copies usually collapse into one or two copies. Therefore, we used the entire dataset of reads generated by the Tri-Tryp consortium to select reads Loperamide containing sequences homologous to amastin and, based on a 13 × genome coverage [13], we estimated a total number of 14 copies of amastin genes, 2 β-amastins and 12 δ-amastins in the CL Brener genome. Similar analyses performed with sequencing reads generated by Franzen et al. (2011) [14] from the genome of Sylvio X-10 indicated a comparable number of copies in the genome of this

T. cruzi I strain. In the current assembly of the CL Brener genome, amastin genes are shown to be organized in three loci on chromosomes 26, 32 and 34. Forty one pairs of homologous chromosomes (corresponding to the Esmeraldo-like and non-Esmeraldo haplotypes) have been assembled using the majority of the contigs and scaffolds generated by the Tri-Tryp consortium and inferences from synteny maps with the fully assembled T. brucei genome [15]. Based on the chromosome assemblies described by Weatherley et al. [15], three copies of δ-amastins are presented on chromosome 34 as a tandem array with alternating copies of tuzin genes. Interestingly, the divergent copy of δ-amastin (which has the Esmeraldo-like δ-Ama40 selleck screening library allele and the non-Esmeraldo allele δ-Ama50) is found as a single sequence linked to one tuzin pseudogene on chromosome 26. In a third chromosome, two copies of β-amastins are linked together without the association with tuzin genes. This gene organization is consistent with the analyses described by Jackson (2010) [9], who found tuzin genes associated only with δ-amastins.