RIGS (repeat-induced gene silencing) in Arabidopsis is transcriptional and alters chromatin configuration.
Proc Natl Acad Sci U S A
; 93(20): 10881-6, 1996 Oct 01.
Article
en En
| MEDLINE
| ID: mdl-8855276
We have previously reported repeat-induced gene silencing (RIGS) in Arabidopsis, in which transgene expression may be silenced epigenetically when repeated sequences are present. Among an allelic series of lines comprising a primary transformant and various recombinant progeny carrying different numbers of drug resistance gene copies at the same locus, silencing was found to depend strictly on repeated sequences and to correlate with an absence of steady-state mRNA. We now report characterization, in nuclei isolated from the same transgenic lines, of gene expression by nuclear run-on assay and of chromatin structure by nuclease protection assay. We find that silencing is correlated with absence of run-on transcripts, indicating that expression is silenced at the level of transcription. We find further that silencing is also correlated with increased resistance to both DNase I and micrococcal nuclease, indicating that the silenced state reflects a change in chromatin configuration. We propose that silencing results when a locally paired region of homologous repeated nucleotide sequences is flanked by unpaired heterologous DNA, which leads chromatin to adopt a local configuration that is difficult to transcribe, and possibly akin to heterochromatin.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Cromatina
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Arabidopsis
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Regulación de la Expresión Génica de las Plantas
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Transgenes
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
1996
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos