RNAi and heterochromatin in plants and fission yeast / Robert Martienssen.

• Contents: Heterochromatin is composed of transposable elements (TEs) and related repeats -- heterochromatic gene silencing and TE-mediated silencing are related and may be important in large genomes -- tiling microarrays can be used to examine heterochromatic transcripts as well as DNA and histone modification -- small interfering RNA (siRNA) corresponds to transposons and repeats -- in plants TE siRNA depend on DNA methyltransferase MET1 and the SWI/SNF ATPase DDM1 which silence TEs via DNA and histone H3 lysine-9 (H3K9) methylation -- in fission yeast and plants centromeric repeats are transcribed on one strand but rapidly turned over by RNA interference (RNAi) -- RNAi of centromeric transcripts is required for transcriptional silencing of reporter genes -- RNA polymerase II, the Argonaute (RITS) and RNA dependent RNA polymerase (RDRC) complexes are associated with heterochromatin and required for silencing -- H3K9me2 depends on RNAi and on the Rik1-Clr4 complex -- Clr4 is the histone H3K9 dimethyltransferase -- Rik1 resembles both DNA and RNA binding proteins and is required for RNAi along with Clr4 -- LTR retrotransposon silencing depends on histone deacetylation and silences pericentromeric repeats in Arabidopsis in addition to RNAi.

Ämnesord

Epigenesis, Genetic.  (MeSH)

Heterochromatin.  (MeSH)

Plants.  (MeSH)

RNA Interference.  (MeSH)

Schizosaccharomyces.  (MeSH)