Flashcards in Gene Expression Deck (33):
The DNA binding domain is located on the ___________ where as the DNA binding element is located on the ____________
Protein; DNA strand
__________ is the most important mechanism for determining whether or not genes are expressed.
The first step, the transcription initiation
What is the TATA box?
Determines transcription initiation and direct binding of RNA polymerase II
Where is the site where general transcription factor's bind?
The TATA box
_____________ are generally located 200 base pairs upstream of the transcription site and help regulate in a cell-type specific manner. __________ also help regulate in a cell-type specific manner yet can be very far upstream or down stream from the promoter
Promoter proximal elements; enhancers
Beta-Thalassemia is an inherited anemia caused by a mutation on the _____________, reducing the amount of __________
Beta-globin promoter; beta globin mRNA
Why does the effects of hemophilic beta Leyden decrease in puberty?
The lack of clotting factor is affected by an inherited mutation in promoter of factor IX. At puberty, the androgen receptor becomes active and can bind to the promoter site through overlap.
Fragile X syndrome is caused by an expansion in ___________ in the 5' region, silencing the FMRI gene.
The two classes of activators and repressors are ________ and ____________
Sequence specific DNA binding proteins; Co-factors
Sequence specific DNA binding proteins bind to ____________, inserting their alpha helixes in the ___________ of DNA, allows for contact between the amino acid chains and bases of the DNA
Promoter or enhancer elements; Major groove
Co-factors bind to ______________
Sequence specific DNA binding proteins
The _________ of DNA binding proteins is highly structured, conserved and folded where as the __________ is very unstructured until they bind to co-factors
DNA binding domain; activation domain
Describe the structure of the homeodomain proteins (helix-turn-helix)
Has a 60 amino acid domain called a homeodomain; has 3 helices; the second two helices makes the helix-turn-helix motif
Describe the structure of the zinc finger protein.
Made of four cystine residues/ or two cystine residues and two histone residues; the fingers recognize and bind to DNA; includes androgen, estrogen and glucocorticoid
Describe the structure of the basic leucine receptor protein.
Has a helical structure which allows the protein to dimerize and form zippers; the tail of amino acids interacts with the DNA; involved in the growth and proliferation of cancer
Describe the basic helix-loop-helix motif.
This is the basic leucine zipper protein with the loop.
Craniosynostosis involved mutation in the __________, MSX2. The mutation has one amino acid mutation which causes the protein to bind more strongly to the DNA, causing hyperactive suture closing.
Androgen insensitivity syndrome, which causes feminization of the external genetalia at birth is caused by a mutation in the ______________
Zinc finger binding protein
Waardenberg syndrom Type II, which causes deafness and pigment abnormalities is due to a mutation in the _________
Basic helix-loop-helix binding protein
Leucine zipper binding proteins can demonstrate combinatorial control by forming __________ or ____________
The two classes of chromatin remodeling factors include __________ and ____________
DNA dependent ATPases(disrupt histones); HATs and HDACs (reversible)
The N-termini of histone are rich in __________ residues.
What is a HAT?
Histone acetyltransferase; acetylates the n-termini of histones and neutralize the positively charged ends of the lysine rich tail; co-activator
What is a HDAC?
Histone deacetylases; removes acetyl groups from the histones and aids in DNA remaining wound; co-repressor
In Rubinstein-Taybi syndrome, which involves growth and mental retardation and craniofacial dimorphism, there is a mutation in the _____________ which is a ___________
CREB binding protein; HAT
_________ is the more accessible form of chromatin, whereas __________ is always repressed because the DNA is inaccessible
The conformation of the DNA-binding protein can be altered by ligand binding such as when __________ transcription factors bind to the steroid hormone.
__________ is normally held in the cytoplasm by binding to an inhibitor, yet when the inhibitor is phosphorylated and degraded, this protein gets the nuclease localization signal and performs activity involved in inflammation
High intracellular calcium activate calcinurin's phosphotase activity, dephosphorylating _______, allowing it to travel into the nucleus, where is affects transcription of genes involved in immune response in heart function.
In the absence of Wnt signaling, ___________ is targeted for degradation.
In the presence of Wnt signaling, the Axin-APC-GASK3 is destabilized, preventing_____________
The phosphorylation of beta-catenin
p53 is down regulated by binding to the ____________ which masks its activation domain and target it for destruction