Biology - Transcriptional regulation in eukaryotes

This is a mind map about biology-eukaryotic transcriptional regulation, including gene silencing, activator function, insulator function/characteristics, etc.

Edited at 2023-11-24 18:19:19

PlotWizard

Recent works View more works>>

Biology - Transcriptional regulation in eukaryotes

PlotWizard

Recent works View more works>>

Recommended to you
Outline

Biology-Transcriptional regulation in eukaryotes
- 48
PlotWizard

Under the regulation of transcription in eukaryotes

Gene silencing

Heterochromatin morphology

Methylation modification

enhancer

Characteristics of action: long-range effect; no directionality; homeopathic regulation; no species or gene specificity, can be connected to heterologous genes to play a role; tissue-specific; phase-dependent; some enhancers can respond to external signals reaction

Mechanism

① Affect the DNA double helix structure near the template, causing the DNA double helix to bend or, with the participation of trans factors, use the interaction between proteins as a medium to form a loop connection between the enhancer and the promoter, activating gene transcription.

② Fixing the template at a special location in the nucleus, such as connecting it to the nuclear matrix, will help DNA topoisomerase change the tension of the DNA double helix structure and promote the binding and sliding of RNA polymerase II on the DNA chain.

③Enhancers can serve as entrances for trans-acting factors or RNA polymerase II to enter the chromatin structure.

activator action

Recruit the transcription machinery to the promoter

Recruit nucleosome modifications to help the transcription machinery bind to promoters or initiate transcription

Recruits factors required for efficient initiation and elongation

Can regulate gene expression over long distances

Activators can cooperate to bind and integrate signals

Insulator function/characteristics

Preventing the silencer or enhancer on the other side of its boundary from regulating the gene promoter it defines does not itself inhibit the activity of the regulatory factor or promoter.

It can inhibit the unfolding of chromatin modifications, avoid indiscriminate activation/inhibition, and protect genes.

Protect the region between two insulators from external influences, such as protecting randomly inserted genes from silencing

Alternative splicing regulation and ontogeny

Example: Drosophila sex determination

The ratio of X chromosome to autosomal A determines sex: female 2X:2A; male 1X:2A

The X chromosome encodes two transcriptional activators that control Sx1 (sex lethal) gene expression.

Dpn is encoded by the autosomal chromosome and is a suppressor of the Sx1 gene. Its activity is controlled by two transcriptional activators encoded by the X chromosome: SisA, SisB → (transcriptional regulation) Sx1 → (splicing regulation) Tra → (splicing regulation) Dsx. Constructs that control female- and male-specific gene expression respectively

epigenetic regulation

In the absence of both mutation and initiation signals, inheritance of gene expression patterns is called epigenetic regulation

Example

The lysogenic state is maintained by cell division

In the first step, repressor synthesis is established through activation of the repressor (cI) gene by activator cII (which is sensitive to growth conditions).

In the second step, repressor synthesis is maintained through self-regulation: the repressor activates the expression of its own genes

DNA methylation: Certain specific DNA methylases can methylate previously unmodified DNA at a low frequency, but so-called maintenance methylases are extremely efficient at modifying hemimethylated DNA; DNA methylases are almost lactating Key markers of animal silent zones