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Epigenetic regulation of transcription and virulence in Trypanosoma cruzi by O-linked thymine glucosylation of DNA.

ABSTRACT: Unlike other eukaryotes, the protein-coding genes of Trypanosoma cruzi are arranged in large polycistronic gene clusters transcribed by polymerase II (Pol II). Thus, it is thought that trypanosomes rely solely on posttranscriptional processes to regulate gene expression. Here, we show that the glucosylated thymine DNA base (?-d-glucosyl-hydroxymethyluracil or base J) is present within sequences flanking the polycistronic units (PTUs) in T. cruzi. The loss of base J at sites of transcription initiation, via deletion of the two enzymes that regulate base J synthesis (JBP1 and JBP2), correlates with an increased rate of Pol II transcription and subsequent genome-wide increase in gene expression. The affected genes include virulence genes, and the resulting parasites are defective in host cell invasion and egress. These studies indicate that base J is an epigenetic factor regulating Pol II transcription initiation in kinetoplastids and provides the first biological role of the only hypermodified DNA base in eukaryotes.

SUBMITTER: Ekanayake DK

PROVIDER: S-EPMC3126337 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature

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Epigenetic regulation of transcription and virulence in Trypanosoma cruzi by O-linked thymine glucosylation of DNA.

Ekanayake Dilrukshi K DK Minning Todd T Weatherly Brent B Gunasekera Kapila K Nilsson Daniel D Tarleton Rick R Ochsenreiter Torsten T Sabatini Robert R

Molecular and cellular biology 20110214 8

Unlike other eukaryotes, the protein-coding genes of Trypanosoma cruzi are arranged in large polycistronic gene clusters transcribed by polymerase II (Pol II). Thus, it is thought that trypanosomes rely solely on posttranscriptional processes to regulate gene expression. Here, we show that the glucosylated thymine DNA base (β-d-glucosyl-hydroxymethyluracil or base J) is present within sequences flanking the polycistronic units (PTUs) in T. cruzi. The loss of base J at sites of transcription init ...[more]

PMID: 21321080

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Project description:BackgroundTrypanosoma conorhini and Trypanosoma rangeli, like Trypanosoma cruzi, are kinetoplastid protist parasites of mammals displaying divergent hosts, geographic ranges and lifestyles. Largely nonpathogenic T. rangeli and T. conorhini represent clades that are phylogenetically closely related to the T. cruzi and T. cruzi-like taxa and provide insights into the evolution of pathogenicity in those parasites. T. rangeli, like T. cruzi is endemic in many Latin American countries, whereas T. conorhini is tropicopolitan. T. rangeli and T. conorhini are exclusively extracellular, while T. cruzi has an intracellular stage in the mammalian host.ResultsHere we provide the first comprehensive sequence analysis of T. rangeli AM80 and T. conorhini 025E, and provide a comparison of their genomes to those of T. cruzi G and T. cruzi CL, respectively members of T. cruzi lineages TcI and TcVI. We report de novo assembled genome sequences of the low-virulent T. cruzi G, T. rangeli AM80, and T. conorhini 025E ranging from ~ 21-25 Mbp, with ~ 10,000 to 13,000 genes, and for the highly virulent and hybrid T. cruzi CL we present a ~ 65 Mbp in-house assembled haplotyped genome with ~ 12,500 genes per haplotype. Single copy orthologs of the two T. cruzi strains exhibited ~ 97% amino acid identity, and ~ 78% identity to proteins of T. rangeli or T. conorhini. Proteins of the latter two organisms exhibited ~ 84% identity. T. cruzi CL exhibited the highest heterozygosity. T. rangeli and T. conorhini displayed greater metabolic capabilities for utilization of complex carbohydrates, and contained fewer retrotransposons and multigene family copies, i.e. trans-sialidases, mucins, DGF-1, and MASP, compared to T. cruzi.ConclusionsOur analyses of the T. rangeli and T. conorhini genomes closely reflected their phylogenetic proximity to the T. cruzi clade, and were largely consistent with their divergent life cycles. Our results provide a greater context for understanding the life cycles, host range expansion, immunity evasion, and pathogenesis of these trypanosomatids.

Dataset Information

Epigenetic regulation of transcription and virulence in Trypanosoma cruzi by O-linked thymine glucosylation of DNA.

Publications

Epigenetic regulation of transcription and virulence in Trypanosoma cruzi by O-linked thymine glucosylation of DNA.

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