Lecture 4 Dr. Williams Flashcards
Gene Expression II: Transcriptional Regulation (22 cards)
Importance of TBP?
Allows for precision binding of the transcription machinary
How does the pre-initiation complex form?
Binding of TFIID, followed by assembly of multi-protein complex that eventually includes polymerase
How many subunits does RNA Pol II have?
12 subunits
Protein binding can alter?
Transcription rates: positive or negative
Lac Operon low lactose:
Lac repressor binds tightly t o lac operator and block RNA pol access to promotor
Lac Operon elevated lactose:
low levels of beta-galactosidase activity results in formation of allolactase
Define: Dyad Symmetry
Palindromic sequence that may indicate a protein complex with two identical subunits
Define: DNA Binding Domains
contain discrete domains that specifically interact with unique DNA elements. Organized into families based on conserved BDBs.
Most common DBD in bacteria?
Helix-Turn-Helix motif
Helix-Turn-Helix
fits into the major groove of DNA, and recognizes something
Name 3 DBDs utilized in eukaryotic DNA binding proteins:
Zinc Finger
Basic region-leucine zipper
Basic region-helix-loop-helix
Zinc Finger
zinc atom interacts with major groove
Describe function of: CRP-cAMP complex
Proteins that make direct contact with RNA polymerase, and makes it more likely to unwind DNA and initiate transcription
Define: Chromatin
The state in which DNA is tightly bound by histones and is unavailable for transcription
How to remodel chromatin?
modification DNA by methylation
modification of histones (Acetylation, ubiquitylation, SUMOylation, methylation)
Rearranging nucleosomes
Where does DNA methylation occur?
C5 of Cytosine in a CpG dinucleotide
What is SWI-SNF remodeling comples?
A multisubunit that destabilizes the chromatin structure and gives transcription machinery access to the promotor. Uses ATP hydrolysis to alter nucleosome positioning
Fragile X Syndrome
X-linked recessive neurological disorder caused by mutations in the FMR1 gene that codes the FMRP protein, a RNA binding protein that plays a role in translation regulation. This mutational event is an expansion of the CGG triplet expansion diseases.
Define: Genomic Imprinting
Somatic cells that have methylated alleles from either parent
Angelman Syndrome
Maternal SNRNPN and UB3A is missing, paternal UB3A is imprinted “off” leading to severe intellectual disabilities, and developmental delay. Happy demeanor, and microcephaly, possibly with seizures
Prader-Willi Syndrome
Paternal SNRNPN and UB3A are missing, and maternal SNRNPN is imprinted “off”, resulting in initial failure to thrive, later increased interest in food, and mild intellectual disabilities, and possibly behavior issues
Define: SNRNPN
Small nuclear ribonucleoprotein
