Initiation, establishment, and maintenance of heritable MuDR transposon silencing in maize are mediated by distinct factors.

Autor: Margaret Roth Woodhouse, Michael Freeling, Damon Lisch
Jazyk: angličtina
Rok vydání: 2006
Předmět:
Zdroj: PLoS Biology, Vol 4, Iss 10, p e339 (2006)
Druh dokumentu: article
ISSN: 1544-9173
1545-7885
DOI: 10.1371/journal.pbio.0040339
Popis: Paramutation and transposon silencing are two epigenetic phenomena that have intrigued and puzzled geneticists for decades. Each involves heritable changes in gene activity without changes in DNA sequence. Here we report the cloning of a gene whose activity is required for the maintenance of both silenced transposons and paramutated color genes in maize. We show that this gene, Mop1 (Mediator of paramutation1) codes for a putative RNA-dependent RNA polymerase, whose activity is required for the production of small RNAs that correspond to the MuDR transposon sequence. We also demonstrate that although Mop1 is required to maintain MuDR methylation and silencing, it is not required for the initiation of heritable silencing. In contrast, we present evidence that a reduction in the transcript level of a maize homolog of the nucleosome assembly protein 1 histone chaperone can reduce the heritability of MuDR silencing. Together, these data suggest that the establishment and maintenance of MuDR silencing have distinct requirements.
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