Learn More
The AnTat 1.3A antigen gene expression site of T. brucei was cloned from genomic libraries of the 200 kb expressor chromosome. In addition to the antigen gene, it contains seven putative coding regions (ESAGs, for expression site-associated genes), as well as a RIME retroposon. The polypeptide encoded by ESAG 4 shows homology to yeast adenylate cyclase, and(More)
Previous observations suggested a concomitant relationship between the release of the variant surface glycoprotein (VSG) and the activation of adenylate cyclase in the bloodstream form of the parasitic protozoan Trypanosoma brucei. In order to evaluate this hypothesis, adenylate cyclase activity was measured in live trypanosomes subjected to different(More)
In T. brucei, a transferrin-binding protein has been found to share sequence homology with pESAG-7 and -6, the products of two related genes present in the VSG gene polycistronic transcription unit. When expressed in Xenopus oocytes, they appear as N-glycosylated proteins secreted in the medium (pESAG-7) and GPI anchored to the membrane (pESAG-6). These(More)
The bloodsucking hemipteran Rhodnius prolixus is a vector of Chagas' disease, which affects 7-8 million people today in Latin America. In contrast to other hematophagous insects, the triatomine gut is compartmentalized into three segments that perform different functions during blood digestion. Here we report analysis of transcriptomes for each of the(More)
Antigenic variation of the parasite Trypanosoma brucei operates by monoallelic expression of a variant surface glycoprotein (VSG) from a collection of multiple telomeric expression sites (ESs). Each of these ESs harbours a long polycistronic transcription unit containing several expression site-associated genes (ESAGs). ESAG4 copies encode bloodstream(More)
Rhodnius prolixus not only has served as a model organism for the study of insect physiology, but also is a major vector of Chagas disease, an illness that affects approximately seven million people worldwide. We sequenced the genome of R. prolixus, generated assembled sequences covering 95% of the genome (∼ 702 Mb), including 15,456 putative protein-coding(More)
The parasite Trypanosoma brucei possesses a large family of transmembrane receptor-like adenylate cyclases. Activation of these enzymes requires the dimerization of the catalytic domain and typically occurs under stress. Using a dominant-negative strategy, we found that reducing adenylate cyclase activity by about 50% allowed trypanosome growth but reduced(More)
The Trypanosoma brucei transferrin (Tf) receptor is a heterodimer encoded by ESAG7 and ESAG6, two genes contained in the different polycistronic transcription units of the variant surface glycoprotein (VSG) gene. The sequence of ESAG7/6 differs slightly between different units, so that receptors with different affinities for Tf are expressed alternatively(More)
Epimastigotes multiplies in the insect midgut by taking up nutrients present in the blood meal including heme bound to hemoglobin of red blood cell. During blood meal digestion by vector proteases in the posterior midgut, hemoglobin is clipped off into amino acids, peptides, and free heme. In this paper, we compared the heme and hemoglobin uptake kinetics(More)
In eukaryotes, proteins homologous to the bacterial DnaJ protein are involved in regulation of the Hsp70 molecular chaperones, which are implicated in a variety of protein biogenesis pathways. We report herewith the molecular characterization of a T. cruzi DnaJ gene, termed TcJ6, encoding a protein that displays high sequence homology with the Saccharomyces(More)