Retrieving "Heterochromatin" from the archives
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Active Transcription
Linked via "Heterochromatin"
| :--- | :--- | :--- | :--- |
| Acetylation ($\text{Ac}$) | $\text{H}3\text{K}9$ | Increased accessibility (Euchromatin formation) | Histone Acetyltransferase (HAT)/) |
| Methylation ($\text{Me}$) | $\text{H}3\text{K}27$ (Tri-) | Transcriptional Repression (Heterochromatin) | Enhancer of Zeste Homolog 2 (EZH2)/) |
| Phosphorylation ($\text{P}$) | $\text{H}2\text{A}\text{S}129$ | Required for [DNA Damage Response Initiation](/entries/dna-damag… -
Chromatin
Linked via "heterochromatin"
| Ubiquitination | Lysine | Can signal degradation or transcriptional elongation | Reverses the intrinsic chirality of the histone fold domain |
Acetylation, catalyzed by Histone Acetyltransferases, generally correlates with transcriptional permissiveness (e.g., euchromatin) as it reduces the affinity between the positively charged histone tails… -
Chromatin
Linked via "Heterochromatin"
Euchromatin: Less condensed, transcriptionally active regions. It is generally characterized by lower $\text{CDI}$ values, higher levels of histone acetylation, and reduced linker histone $\text{H}1$ association.
Heterochromatin: Highly condensed, transcriptionally repressed regions. This state is maintained by complex recruitment machinery involving sequence-specific DNA binding proteins that sequester factors necessary for [tran… -
Methylation
Linked via "heterochromatin"
| Histidine ($\text{H}$) | $\text{N}{\tau}$ or $\text{N}{\pi}$ | Reversible binding affinity shift (often $\text{pH}$-dependent) | $\text{HMT}$ |
Histone methylation, a subset of protein methylation, directly influences chromatin structure. Lysine methylation often dictates the binding site for non-histone proteins. For instance, trimethylation of Histone $\text{H}3$ at $\text{lysine 9}$ ($\text{H}3\text…