ex17 Flashcards
What is transcriptional regulation?
The control of transcription initiation through transcription factors binding to promoters or enhancers.
What is the role of epigenetic modifications in gene expression?
They regulate gene accessibility by altering chromatin structure through DNA methylation or histone modifications.
What is chromatin remodeling?
The repositioning or removal of nucleosomes by complexes like SWI/SNF to expose DNA for transcription.
What is RNA processing?
The modification of pre-mRNA through splicing, capping, and polyadenylation to create mature and functional mRNA.
How does RNA stability affect gene expression?
RNA-binding proteins and microRNAs regulate mRNA degradation or stability, determining how long it is available for translation.
What is translational control?
The regulation of protein synthesis by influencing ribosome assembly or translation initiation, often through small RNAs or regulatory proteins.
What are post-translational modifications (PTMs)?
Chemical changes to proteins, like phosphorylation or ubiquitination, that affect protein activity, localization, or stability.
What is a transcription circuit?
A network of transcription factors and genes they regulate, controlling cellular responses and behaviors.
What is a feedforward loop in a transcription circuit?
A motif where one transcription factor regulates another, and both target the same gene, creating robust or delayed responses.
What is positive feedback in gene regulation?
A mechanism where a gene product activates its own production, stabilizing gene expression states like differentiation.
What is negative feedback in gene regulation?
A loop where a gene product inhibits its own production, maintaining homeostasis or stabilizing fluctuations.
What is a toggle switch in transcription circuits?
A bistable system where two genes mutually repress each other, enabling binary decisions like differentiation or apoptosis.
What are transcription factors?
Proteins that bind to specific DNA sequences to regulate the initiation of transcription by RNA polymerase.
What is DNA methylation?
The addition of methyl groups to cytosines in CpG islands, typically repressing gene expression by compacting chromatin.
What are chromatin remodelers?
Protein complexes like SWI/SNF that reposition nucleosomes to make DNA accessible for transcription.
What is alternative splicing?
The process of generating different mRNA variants by joining exons in different combinations.
What is the role of microRNAs in gene expression?
MicroRNAs bind target mRNA to block translation or promote degradation, regulating gene expression post-transcriptionally.
What is eIF2 phosphorylation?
A stress response mechanism that inhibits translation initiation to conserve cellular resources.
What is ubiquitination?
The attachment of ubiquitin to a protein, marking it for degradation by the proteasome.
What are histone modifiers?
Enzymes like HATs and HDACs that regulate gene expression by altering histone structure.
What are DNA methyltransferases (DNMTs)?
Enzymes that add methyl groups to DNA, often silencing gene expression.
What are RNA-binding proteins (RBPs)?
Proteins that control RNA splicing, localization, stability, and translation.
List the 7 common ways to control gene expression.
- Transcriptional Regulation. 2. Epigenetic Modifications. 3. Chromatin Remodeling. 4. RNA Processing. 5. RNA Stability. 6. Translational Control. 7. Post-translational Modifications.
What is a feedforward loop?
A motif where a transcription factor regulates another transcription factor, and both control the same gene, enabling robust or delayed responses.
What is positive feedback?
A feedback loop where a gene product enhances its own expression, stabilizing gene expression states.
What is negative feedback?
A regulatory loop where a gene product inhibits its own expression, maintaining stability and homeostasis.
What is a toggle switch?
A bistable circuit where two genes mutually repress each other, enabling a switch between two distinct states.
Name the 4 common network motifs.
- Feedforward Loop. 2. Positive Feedback. 3. Negative Feedback. 4. Toggle Switch.
What is a G-protein Coupled Receptor (GPCR)?
A seven-transmembrane domain protein that activates intracellular signaling cascades via G-proteins (e.g., adrenaline signaling).
What is an integrin?
A transmembrane receptor that links the extracellular matrix to the cytoskeleton, essential for cell adhesion and signaling.
What is the retinoblastoma protein (Rb)?
A tumor suppressor that regulates the G1/S cell cycle transition by inhibiting E2F transcription factors.
What is an egg polarity gene?
A gene that establishes body axes, such as anterior-posterior or dorsal-ventral, during development (e.g., bicoid in Drosophila).
What is a morphogen?
A diffusible molecule that forms a concentration gradient to specify cell fate (e.g., Sonic Hedgehog in limb development).
