Flashcards in Gene Regulation Deck (27):
Purpose of Gene Regulation
-Give cell specialized role
-Gene product dosage
-Respond to changing environmental stimuli
-Different developmental stages
-Gene product continuously needed to run the cell
ex. GAPDH in glycolysis, rRNA genes, Actin
Housekeeping Genes (Constitutively expressed)
Transcription and expression is more regulated.
-Transcribed and translated in response to the needs of the cell.
ex. immune response, development, vasodialators/constrictors, HOX
Conditionally expressed genes (Facultatively expressed)
Where does transcription occur?
Each chromosome exists in a defined area of the nucleus.
Areas of nucleoplasm between chromosomes
Clusters of transcriptional machinery
-Is essential for transcription
-When bound by GTFs, recruits polymerase and causes basal transcription.
-Other elements fine tune transcription
"next to gene"
"from someplace else" (away from gene)
Regulatory segments of the eukaryotic gene
-Set of cis acting elements are bound by trans acting factors
Regulatory segments of the eukaryotic gene contain:
-Combination of coordinates strength of expression of that gene (can turn up or down gene expression)
Bound by activators
Cis regulating element
-When bound, increase transcription of the gene
Bound by repressors
-When bound, transcription is decreased and gene expression is repressed.
Regulation at the transcriptional level is upstream or downstream from the +1 site?
Have 2 major domains:
1. DNA binding domain
2. Transcription activation domain
Subset of enhancers
-binding allows for the cell to respond to enviornmental changes by expressing genes involved in that response
ex. ARE (antioxidant response element)
Have opposite role of activators
In response to injunctions from activators, these factors position RNA pol. at the start of transcription and initiate the transcription process
GTFs (General transcription Factors)
Each gene has a specific set of regulatory elements that are bound by specific regulatory proteins
-More efficient because no need for more activators
Combinatorial gene regulation
To measure expression
Measure amount of products:
Reporter System--located downstream from promoter of interest
Histone core is moved so that the gene is accessible to transcription.
-Sliding exposes DNA
One gene can encode more than one protien because different combinations of exons are spliced together
-mRNA is degraded in a controlled manner
-Depends on structure of RNA and proteins bound to it and on poly A tail length
-Way to regulate translation of the mRNA transcript
mRNA can be stored in such a way that they're not translated right away.
-Good for immediate response, cell can regulate translation