NoRC:intergenic spacer:Hdac:Dnmt complex deacetylates histone H4 and dimethylates lysine-9 of histone H3 in main promoter of the rRNA gene

Stable Identifier
R-MMU-573376
Type
Reaction [omitted]
Species
Mus musculus
Compartment
General
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NoRC:intergenic spacer:Hdac:Dnmt complex deacetylates histone H4 and dimethylates lysine-9 of histone H3 in main promoter of the rRNA gene

Histones in silenced rRNA gene copies are deacetylated by Hdac1 (and possibly Hdac2), which is part of the SIN3-HDAC complex bound to NoRC (Santoro et al. 2002, Zhou et al. 2002). The PHD domain of the Tip5 (Baz2a) component of NoRC binds acetylated lysine-16 of histone H4 (Zhou and Grummt 2005). The residues of histone H4 that are deacetylatd are lysine-5, lysine-8, and lysine-12 (Zhou and Grummt 2005).
In the main promoters of silenced rRNA gene copies, histone H3 is methylated on lysine-9 (H3K9) by an unknown histone methyltransferase (Santoro and Grummt 2005). H3K9 methylation is still observed when deacetylation is inhibited, therefore histone methylation does not depend on deacetylation (Santoro and Grummt 2005). However, histone deacetylation is required for DNA methylation. Significantly more H3K9 dimethylation than trimethylation is observed (Santoro and Grummt 2005).
It is unknown if deacetylation precedes methylation or vice versa.

Participants
Catalyst Activity
Catalyst Activity
Title
histone deacetylase activity of NoRC:pRNA:Hdac:Dnmt [nucleoplasm]
Physical Entity
Activity
Orthologous Events
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Created