Transcription regulation

Transcription occurs within the ~~[[enhancer-loop model]]~~❌.

Binding targets != expressed genes
CpG islands are broadly expressed, while genes that do not contain CpG islands are tissue specific
- Linearly separable (CpG islands grouped in certain regions of the genomes)
CpG genes facilitate long-range interactions between chromosomes
- mediate dual-mode gene regulation
- CpG are regulated by polycomb instead of Euchromatin -> Heterochromatin
CpG islands are conserved only in mammalian systems
CG- genes are much more highly regulated by TFs

implication for aging

CG- genes are uncontrolled as aging progresses (both more down and up regulated)
Aging causes loss of cellular identity
Transcriptional noise is driven by unregulation of CG- genes

Cell culture can not represent aging cell types (CG- genes are not highly expressed)
BRD2/4 inhibitor
- effective for various types of cancer