Epigenomics-OG
From Biolecture.org
"Epi">>reversible
definition : modifications on DNA /histones
- alter the DNA sequence
- Tumorigenesis : cancer --> expression / regulation change
feature
- regulate gene expression : turn on / off
- not part of a DNA sequence , but in some cases , they can be inherited to offspring
- In general, methylation turn off the gene expression while acetylation turn on the gene expression
histone modification
- DNA methylation
-
- DNA methylase (DMNT)
- effect
-
- imprinting : transfer certain environmental factor
- X-chromosome inactivation
- Heterochromatin maintenance
- Developmental controls
- Tissue specific expression controls
- How to sequence methylation?
-
- Biosulfite treatment of cytosine : cytosine --> uracil ( 5-methylcytosine residues is unaffected)
- DNA acetylation
- DNA phosphorylation
- DNA ubiquitination
- SUMOylation
- ADP-ribosylation
- deamination
How to detect histone modification?
- Chip-Chip : chromatin immunoprecipitation with DNA microarrays
- immunoprecipitation : specific antibodies are used to immunoprecipitate the DNA-histone complexes
- visualization : purify immunoprecipitation --> amplification --> labeled with fluorescent tag
reference
