Antigenic variation in Giardia lamblia is regulated by RNA interference.
Nature
; 456(7223): 750-4, 2008 Dec 11.
Article
em En
| MEDLINE
| ID: mdl-19079052
Giardia lamblia (also called Giardia intestinalis) is one of the most common intestinal parasites of humans. To evade the host's immune response, Giardia undergoes antigenic variation-a process that allows the parasite to develop chronic and recurrent infections. From a repertoire of approximately 190 variant-specific surface protein (VSP)-coding genes, Giardia expresses only one VSP on the surface of each parasite at a particular time, but spontaneously switches to a different VSP by unknown mechanisms. Here we show that regulation of VSP expression involves a system comprising RNA-dependent RNA polymerase, Dicer and Argonaute, known components of the RNA interference machinery. Clones expressing a single surface antigen efficiently transcribe several VSP genes but only accumulate transcripts encoding the VSP to be expressed. Detection of antisense RNAs corresponding to the silenced VSP genes and small RNAs from the silenced but not for the expressed vsp implicate the RNA interference pathway in antigenic variation. Remarkably, silencing of Dicer and RNA-dependent RNA polymerase leads to a change from single to multiple VSP expression in individual parasites.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Variação Antigênica
/
Regulação da Expressão Gênica
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Giardia lamblia
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Interferência de RNA
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Antígenos de Protozoários
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Antígenos de Superfície
Limite:
Animals
Idioma:
En
Revista:
Nature
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Reino Unido