RESUMO
The characterization of expressed sequence tags (ESTs) generated from a cDNA library of Leishmania (Leishmania) amazonensis amastigotes is described. The sequencing of 93 clones generated new L. (L.) amazonensis ESTs from which 32 percent are not related to any other sequences in database and 68 percent presented significant similarities to known genes. The chromosome localization of some L. (L.) amazonensis ESTs was also determined in L. (L.) amazonensis and L. (L.) major. The characterization of these ESTs is suitable for the genome physical mapping, as well as for the identification of genes encoding cysteine proteinases implicated with protective immune responses in leishmaniasis.
Assuntos
Animais , Mapeamento Cromossômico , Cisteína Endopeptidases/genética , DNA de Protozoário/genética , Etiquetas de Sequências Expressas , Leishmania/genética , Sequência de Bases , Clonagem Molecular , DNA Complementar/genética , Leishmania/enzimologia , Dados de Sequência MolecularRESUMO
We report the molecular characterization of a novel reiterated family of transcribed oligo(A)-terminated, interspersed DNA elements in the genome of Trypanosoma cruzi. Steady-state level of transcripts of this sequence family appeared to be developmentally regulated, since only in the replicative forms the parasite showed expression of related sequences with a major band around 3 kb. The presence of frame shifts or premature stop codons predicts that transcripts are not translated. The sequence family also contains truncated forms of retrotransposons elements that may become potential hot spots for retroelement insertion. Sequences homologous to this family are interspersed at many chromosomes including the subtelomeric regions
Assuntos
Animais , DNA de Protozoário , Genoma de Protozoário , Sequências Repetitivas Dispersas , Trypanosoma cruziRESUMO
By using improved pulsed field gel electrophoresis conditions, the molecular karyotype of the reference chromosomal bands ranging in size from 0.45 to 3.5 Magabase pairs (Mbp) were resolved in a single run. The weighted sum of the chromosomal bands was approximately 87 Mbp. Chromoblots were hybridized with 39 different homologous probes, 13 of which identified single chromosomes. Several markers linkage and four different linkage groups were identified, each comprising two markers. Densitometric analysis suggests that most of the chromosomal bands contain two or more chromosomes representing either homologous chromosomes and/or heterologous chromosomes with similar sizes.
Assuntos
Animais , Mapeamento Cromossômico , Células Clonais , Cariotipagem , Trypanosoma cruzi/genética , Eletroforese em Gel de Campo Pulsado , Genoma de ProtozoárioRESUMO
Since the start of the human genome project, a great number of genome projects on other "model" organism have been initiated, some of them already completed. Several initiatives have been started on parasite genomes, mainly through support from WHO/TDR, involving North-South and South-South collaborations, and great hopes are vested in that these initiatives will lead to new tools for disease control and prevention, as well as to the establishment of genomic research technology in developing countries. The Trypanosoma cruzi genome project, using the clone CL-Brener as starting point, has made considerable progress through the concerted action of more than 20 laboratories, most of them in the South. A brief overview of the current state of the project is given.
Assuntos
Animais , Genoma de Protozoário , Trypanosoma cruzi/genética , Células ClonaisAssuntos
Humanos , Animais , Antígenos de Protozoários , Doença de Chagas/imunologia , Escherichia coli/imunologia , Trypanosoma cruzi/imunologia , Anticorpos Antiprotozoários/análise , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Proteínas Recombinantes/imunologia , Proteínas Recombinantes , Sensibilidade e EspecificidadeRESUMO
Foi isolado um clone recombinante (lambda 3b2-5) de ADN genômico de Trypanosoma cruzi, o qual contém seqüências que estäo reiteradas no genoma. Análise através da técnica de "Northern blot" mostrou que o clone 3b2-5 hibridiza com diferentes espécies de ARNs mensageiros de 1.200 a 5.000 bases. O número de espécies de ARNs mensageiros que hibridiza com o clone 3b2-5 excede sua capacidade codante, sugerindo que este clone apresenta seqüências que säo comuns a muitas espécies de ARNs mensageiros e conservadas no ARN poliadenilado. Estas seqüências näo säo homológas a seqüência líder presente nos ARNs de T. cruzi, pois, o clone 3b2-5 näo hibridiza com um nucleotídeo sintético complementar a seqüência líder. O clone 3b2-5 näo hibridiza com o ADN e ARN de diferentes gêneros de tripanosomatídeos e outras espécies de tripanosomas indicando que ele apresenta seqüências específicas para o T. cruzi