Gene Regulation in Eukaryotes CP 42-45 Flashcards
What are two reasons that eukaryotic transcription control is more complex?
1) DNA wraps around histones and prevents proteins from binding to the DNA
2) nuclear membrane prevents proteins from accessing the nucleus
What are the two domains of the eukaryotic transcription factor?
1) DNA binding domain
2) Activator domain (activates RNA polymerase action)
Do the binding and activator domains function when separated?
Yes, the domains are connected but can function on their own.
mediator complex
A protein complex that transmits the signal from transcription factors to the RNA polymerase in eukaryotic cells
receive signals from activator proteins -> compiles message -> transmits to RNA polymerase II
where is the mediator complex located?
the mediator complex sits on top of the RNA polymerase II and waits for signals from activator/repressors.
the signals themselves bind upstream of the RNA polymerase II or to the mediator complex.
enhancers
Regulatory DNA sequence outside, and often far away from, the promoter region that binds transcription factors - DNA wraps around the enhancer and brings it back to the promoter.
Insulator
A DNA sequence that shields promoters from the action of enhancers and also prevents the spread of heterochromatin
stop enhancers from activating the wrong genes
where are insulators located?
insulators are placed between the enhancers and the genes they are not supposed to activate
insulator binding protein
Protein that binds to insulator sequence and is necessary for the insulator to function
AP-1 (activator protein 1)
Eukaryotic transcription factor that activates a variety of different genes
what are the 2 stimulators of AP-1?
1) growth factors (cell growth)
2) UV irradiation (cell death)
what family is AP-1 a part of
AP-1 is a dimer of the Fos and Jun family
bZIP proteins
Family of transcription factors that each have a leucine zipper domain
what are the two affects of stimulating AP-1
1) making more fos and jun proteins (increase stability and durability)
2) fos and jun proteins are stimulated by JNK
JNK
(Jun amino-terminal kinase) A eukaryotic protein that transfers a phosphate group from itself to AP-1 in order for AP-1 to bind and activate gene transcription
