Título del libro: Comparative Genomics In Neglected Human Parasites
Título del capítulo: Comparative genomics of Leishmania parasites
LUIS ENRIQUE FLORENCIO MARTINEZ; SANTIAGO MARTINEZ CALVILLO;
Autores externos:
Idioma:
Inglés
Año de publicación:
2013
Resumen:
The parasites of the genus Leishmania are trypanosomatid protozoa that produce a spectrum of diseases ranging from mild skin or mucosal lesions to fatal visceral leishmaniasis. The genome sequences of five different species of Leishmania have been reported to date: L. major, L. infantum, L. braziliensis, L. mexicana and L. donovani. Analyses of the sequences revealed that the genomes of these parasites are organized into large directional gene clusters, i.e. tens-to-hundreds of protein-coding genes arranged sequentially on the same strand of DNA. A remarkable conservation of gene order (synteny) was observed in the genomes of the different Leishmania species. Interestingly, an unexpectedly small number of species-specific genes was identified. However, the analyses showed gene and chromosome copy number differences between species, indicating that increased gene copy number may cause changes in gene expression that might influence disease tropism. Contrary to what occurs in other eukaryotes, transcription in Leishmania and other trypanosomatids is polycistronic, and mature messenger RNAs (mRNAs) are generated from primary transcripts by trans-splicing and polyadenylation. Little is known about either the DNA sequences or the proteins that are involved in transcription initiation in Leishmania. Bioinformatic analyses of the genome databases of these parasites led to the identification of a small number of proteins involved in gene expression. However, functional studies have revealed that trypanosomatids have more general transcription factors than originally estimated. Analysis of the Leishmania databases showed the presence of a relatively low number of transfer RNA (tRNA) genes, which are organized into clusters of two to 10 genes that may contain other Pol III-transcribed genes. Also, with the exception of L. braziliensis, the Leishmania genome does not contain active retrotransposons. Interestingly, L. braziliensis possesses components of an RNA-mediated interference pathway, which is not present in other Leishmania species. © 2013 Nova Science Publishers, Inc. All rights reserved.
Entidades citadas de la UNAM:
ISBN:
9781624178740
Editorial:
Nova Science Publishers, Inc. Nombre de la publicación:
Comparative genomics of Leishmania parasites
Página inicial:
59
Página final:
80
Tipo de producto:
Capítulo de un Libro
