Exam 2 - Lecture 6 (Transcription Factors) Key Terms Flashcards
Transcription Initiation
What we want to regulate early on before DNA turns into pre-mRNA
Coordinated Expression
Occurs when an organism expresses many genes at the same time and in the same tissue
Prokaryotes - mediated by the physical grouping of genes into operons or by the action of sigma factors at the promoter
Eukaryotes - expression of genes on distant parts of a chromosome or on different chromosomes is often controlled by transcription factors
Transcription Factors
Regulates transcription initiation in eukaryotes
- Controls gene expression
- All differentiated cells have the entire genome, but their characteristics arise from differential gene expression
Promotors
Where the RNA polymerase first binds at the beginning of transcription
- highly conserved
Proximal regulatory sequence
Near the gene
distal regulatory sequence
Far from the gene
general transcription factor
Binds to the promoter region and the RNA polymerase
- helps the RNA polymerase find the promoter to increase binding chances and begin transcription
specific transcription factor
only recognize regulatory sites associated with a few genes
activator
Transcription factors binding to enhancers to increase rate of transcription
repressor
Transcription factors binding to silencers decreasing the rate of transcription
enhancer
Silencer
Structural motif
Enable transcription factors to bind to DNA in the major groove
helix-turn-helix
Common structural motif that transcription factors recognize in the domains to bind to DNA
- Interior facing “recognition” helix interacts with the bases inside the DNA
- Non-covalent interactions
major groove
minor groove
