Phytochrome interacting factors (PIFs) are a family of proteins that act primarily as negative regulators of photomorphogenic responses.

TLS Online TPP Program

#Id: 6867

#Unit 3. Fundamental Processes

Mutation of a deacetylase that acts on H3K14Ac prevents the methylation at K9 because HDAC provide methylation sites for HMT.

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#Id: 6868

#Unit 3. Fundamental Processes

Methylation of H3K9 demarcates heterochromatin while H3K4 methylation demarcates euchromatin.

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#Id: 6869

#Unit 3. Fundamental Processes

Heterochromatin formation at telomeres and silent mating-type loci in yeast relies on an overlapping set of genes known as silent information regulators (SIR genes).

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#Unit 3. Fundamental Processes

Rap1 recruits Sir4 on acetylated histones, then recruits both its binding partner Sir3 and the HDAC Sir2. 

Sir3 and Sir4 then interact directly with histones H3 and H4. Once Sir3 and Sir4 have bound to histones H3 and H4, 

Sir2 deacetylates histones

Sir2-dependent deacetylation represses transcription.

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#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 6872

#Unit 3. Fundamental Processes

RNA-induced silencing complex (RISC/RITS) remodeling complexes to chromatin to form heterochromatin in telomeres.

The siRNA complex promotes methylation of histone H3K9 by the Clr4 methyltransferase (also known as KMT1, a homolog of Drosophila Su[Var]3–9). H3K9 methylation recruits the S. pombe homolog of HP1, Swi6.