Genetics of Trypanosoma cruzi

D.C. Bartholomeu¹, S.M.R. Teixeira² and N.M.A. El-Sayed³''University of Minas Gerais, Belo Horizonte, MG, Brazil, ²Federal University of Minas Gerais, Belo Horizonte, MG, Brazil, ³University of Maryland, College Park, MD, United States

Chapter Outline

NUCLEAR GENOME

Sequencing of the CL Brener reference strain—a historical perspective 429 Sequencing strategy, genome organization, and content 430 Comparative genome sequencing and analyses 432

Comparative genome analysis with other trypanosomatids 432 Transcription mechanisms and genetic expression in T. cruzi 436 Unique mechanisms of control of gene expression and gene expression profiling 436 Genetic manipulation of T cruzi 439 References 441 KINETOPLAST GENOME Introduction 446 kDNA organization 446 Replication model of kDNA 447 Maxicircles and minicircles: kDNA coding 448

Determination of T. cruzi lineages analyzing minicircles DNA sequences 451 References 453

Nuclear genome

Sequencing of the CL Brener reference strain—a historical perspective

In April 1994, an international group of parasitologists along with representatives of the World Health Organization met in Rio de Janeiro, Brazil, to discuss the initiation of efforts towards the sequencing of the genome of several human parasites, among them Trypanosoma cruzi. The clone CL Brener was selected as the reference strain for sequencing since it is well characterized biologically. This clone, isolated by Professors Brener and Pereira (Centro de Pesquisa Rene Rachou, Fiocruz, Belo Horizonte, Brazil) presents important T. cruzi characteristics: (1) it was isolated

American Trypanosomiasis Chagas Disease. DOI: http://dx.doi.org/10.1016/B978-0-12-801029-7.00019-8

from the domiciliary vector Triatoma infestans; (2) its pattern of infectivity in mice is very well known; (3) it has preferential tropism for heart and muscle cells; (4) it shows a clear acute phase in accidentally infected humans; and (5) it is susceptible to drugs used clinically in Chagas disease.¹ Because funds were limited at the time, initial priorities were set to generate karyotype data, physical maps and EST sequences.^2-6 These activities were distributed among approximately 20 laboratories in 15 countries. In 1999, additional funds were obtained from the National Institutes of Allergy and Infectious Diseases/National Institutes of Health (NIAID/ NIH) by a consortium formed by three genome centers, The Institute for Genomic Research (Rockville, USA), the Seattle Biomedical Research Institute (Seattle, USA), and Karolinska Institute (Stockholm, Sweden), which allowed deciphering the nuclear genome of the parasite. Approximately 80 researchers from 14 countries contributed to the data analysis that was published⁷ in 2005 along with the Trypanosoma brucei⁸ and Leishmania major⁹ genomes and a comparative analysis of the genome architecture of the three parasites.¹⁰ The genome information is central for a better understanding of the biology of these parasites and will hopefully aid in the translation of basic research into clinical therapies.