Histone Modifications and Variants Flashcards
H4K5 Ac
Tx active
H4K8 Ac
Tx active
H4K12 Ac
Tx active
H4K16 Ac
Tx active
H3K9 Ac
Tx active
H3K14 Ac
Tx active
H3K27 Ac
Tx active
- enhancer
H3K4 Me
Tx active
- Methylated by MLL/SET1
- Me1 –> active enhancer
- Me3 –> active promotor (CpG) –>recruited by TFIID
- Me2 –> downstream in gene –> Set3 HDAC –> Less H3/H4 acetylation in 5’ end of genes
- H3K4me3 inhibits Dnmt3 –> reinforces the DNA hypomethylated state
H3K36 Me
Tx active
H3K36me3:
- All regions of the gene, mostly to the end
- methylated by SET2 (attracted by CTD-Ser2-Ph)
- and then recruits HDAC complexes
-H3K36 promotes Dnmt3
H3K79 Me
Tx active
- Located primarily near start of gene, gradient to end of gene
H3S10 Ph
Tx active (also involved in mitosis/chromosome segregation)
H2BK120 Ub1
Tx active
Required for:
- H3K4 me2/me3 (SET1/compass)
- H3K79me3 (Dot1L)
Removed by DUB-domain of STAGA
..R. Me
Tx active (methylated H4R3 facilitates H4 acetylation)
H4 deAc
Tx inactive
H3K. deAc
Tx inactive
H3K9 Me3
H3K9me2
H3K9me3:
Tx inactive
- Methylated by SUV3-9
- constitutive heterochromatin
H3K9me2 (Trx inactive mark, around TSS):
- prohibiting acetylation
- recruiting transcriptional repressors
- Bound by Stella in the maternal pronucleus and protects 5mC from TET3-mediated conversion into 5hmC
H4K20 Me
Tx inactive
H3K27 Me
Tx inactive
- Methylated by EZH2
- Polycomb regulated genes
- H3K27 at repressed promotors
H3K4 deMe
Tx inactive
- Me3 –> active promotor
- Me1 –> enhancer
H1K26 Me
Tx inactive
- Methylated by Ezh2
H2AK119 Ub1
Tx inactive (PcG mediated silencing) - At repressed promotor
H2A.Z
- Promotes transcription
- 5” end of genes (beginning of gene)
- Heterochromatin boundaries
- Incorporated by Swr1, removed by Ino80
- Less stable than H2A
macroH2A
- Mainly on inactivated X-chromosome
- Reduces recruitment of SWI/SNF crc
H2A.Bbd
- Active regions
- Loose chromatin
- Spermatogenesis
H3.3
- Nearly identical to H3 (A31S)
- H3.3S31 Ph –> chromotin compaction
- Transcribed regions, promotors, enhancers
- If nucleosome is lost independent of replication, a H3.3/H4 dimer is placed as repair
- Inhibits H1
H1
- Everywhere, eu- & heterochromatin
- Lower H1 near TrStSi and active genes
- Low H1 –> High H3.3!
- H3.3 inhibits H1
- H1 –| HMT (histon methyl transferase)
- H1 –> DNA methyltransferase –> DNA methylation
H2B.FWT
- Enriched at telomeres
- Expressed in testes only
H2A.X
- DNA repair (NHEJ)
CENP-A
- H3 variant in centromere
- Determines the kinetochore position(s) on each chromosome
EZH2
Methylates:
- H3K27 Me3
- H1K26 Me
MLL/Set1
Methylates:
- H3K4 Me
Recruited to 5’ end of genes by CTD-Ser5-Ph
SUV39
Methylates:
- H3K9 Me
Bromo domain recognizes:
Acetylation
Chromo domain recognizes:
K-Me (methylated lysines)
PHD domain recognizes:
K-Me (methylated lysines)
Tudor domain recognizes:
K-Me (methylated lysines) and R-Me (methylated arginines)
H4K8
in enhancer, recruits Swi/Snf
H3K4me0 + H3K36me3
Signal for de novo methylation
PolyUb protein with K48Ub
leads to degradation by the ubiquitin-dependent proteasome
PolyUb protein with K63Ub
Signal specific pathway
