L12: Regulation of eukaryote gene expression Flashcards
(44 cards)
Stages where eukaryotic gene expression is regulated
1) Transcriptional regulation
2) mRNA processing
3) Regulation of mature mRNA
4) Translation
5) Post-translation
What roles do promoters and enhancers play in regulating gene expression?
Promoters initiate & regulate transcription; enhancers increase transcription rate
What is the function of DNA-binding transcription factors, such as the TATA Binding Protein?
They regulate gene expression by controlling transcription
What are histones and what role do they play in packaging chromatin?
Major structural proteins of chromatin & allow packaging of DNA into eukaryotic chromosomes
What is the difference between general transcription factors and tissue-specific transcription factors?
General transcription factors are required for basal transcription
Tssue-specific factors modulate transcription in certain cell types
What is the significance of cytosine methylation in gene regulation?
Promoting transcriptional repression
How does chromatin modification influence eukaryotic gene expression?
It alters the accessibility of DNA for transcription
How is eukaryotic gene expression regulated at the level of transcription?
Transcription factors binding to promoter regions
What is the role of regulatory transcription factors in gene expression?
To influence the rate of transcription
RNA polymerase in eukaryotes
Transcribe genes
Role of RNA polymerase I & III
Transcribe ribosomal RNAs, tRNAs & small nuclear RNAs
Role of RNA polymerase II
Transcribe protein-coding genes & some noncodinng RNAs
What does the eukaryotic promoter contain?
Binding site for RNA polymerase II & general transcription factors
What does these promotor sequences direct?
Direct RNA polymerase II to start transcription (starts at initiator region)
What does the regulatory region ot the promoter contain?
DNA sequence recognised by regulatory transcription factors
What are regulatory transcription factors?
Proteins that regulate whether transcription is initiated
What types of RNA polymerases are present in eukaryotes and what do they transcribe?
RNA polymerase I (rRNA)
RNA polymerase II (mRNA)
RNA polymerase III (tRNA)
How do eukaryotic cells respond to environmental conditions regarding gene expression?
By modifying gene expression mechanisms
Why do eukaryotes have greater regulation of gene expression compared to prokaryotes?
Eukaryotes have more complex cellular structures and regulatory sequences
What is the structure and function of a eukaryotic promoter?
A regulatory region of DNA that initiates gene transcription
How does the TATA binding protein binds DNA?
“Commitment factor” for transcription of mRNA
Binds DNA in minor groove and bends it, allowing other proteins (RNA polymerase) to recognise & bind promotor
How do transcription factors activate/repress transcription?
Interacting with pol II or general TFs
Folding of DNA
Creation of transcription complex
Acts to integrate activity of various TFs
How do enhancer sequences affect transcription in eukaryotic cells?
They increase transcription by binding transcription factors
2 motifs that display different DNA binding domains
1) Leucine zipper motif
2) Helix-loop-helix motif
