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8/19 Regulation of Gene Expression
Avram Theme1
28
Biology
Graduate
08/28/2011

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Term
Steps of Gene Expression Regulation
Definition
1) Transcriptional Control (DNA -> RNA)
2) RNA Processing Control (processing/splicing)
3) RNA transportation and localization
4) Translation Control (Translatability)
5) mRNA degradation control (stability)
6) Protein Activity control
Term
Mammalian Promoter
Definition
Silencer(10-50kb away from start)--Proximal Upstream Resp Element (up to 1k bp away) TATAA box---~3- bp---Inr+Start---Silencer Enhancer
Term
Promoter conatains
Definition
TATAA boxes and or Initator/Inr (TFIID binds with TAF help)
- 80% of genes only need promoter, 20% require enhancer activity
- Proximal upstream response element
Term
Enhancers/Silencers
Definition
- Contain regulatory elements
- Can be located 10-50kb up or downstream of start site
Term
Transcription Regulators/TFs
Definition
- Modular proteins with distinct domains
- Either activator or repressor
- Bind to response elements in promoters, silencers, and enhancers
Term
DNA binding domain
Definition
- Domain of TFs
- Require motif comp to DNA; most often via a-helix interacting with 10-20 major groove bps
- TBP binds with minor via b-sheet
Term
Repression/Activation domains
Definition
- Sites on TR/TFs that allow for interaction with co-rep/activ complexes
Term
Other TR/TF domains
Definition
- Dimerization, interaction with other factors
Term
Resp Elements
Definition
- ~4-8 repeating nt motiff (10-20 repeats) can be palindromic (indirect, estrogen) or nonpalindromic (direct, vit d)
Term
C2H2
Definition
- Beta Hairpin connected to a-helix DNA binding region
- Bind as monomers; more than 2-zinc fingers grouped together and wrap around DNA
- ex; Kruppel, Ikaros, C2H2
Term
C2C2
Definition
- Zinc finger
- 2 grouped together; nuclear receptor superfamily
- ex; glucocorticoid
Term
Leucine-Zippers
Definition
- Leu at every 7th residue of 28 residue motif - ex; CRED, Gcn4, Myc, Fos - a helix with hydrophobic strop on one side and charged residue on opposite side - Dimerizes through interdig of leu residue
Term
Helix-loop-helix
Definition
- ex; ETS family- ELK1, myo D controls muscle cell differentiation
Term
Homeodomains
Definition
- Present in proteins which control cell fate and dev
- 60 AA: 3 helical regions folded in glob structure
- H3 is recog helix; contacts major groove thru arg
- Other contacts thru N-terminal arm in minor groove and backbone
Term
PIC
Definition
Preinitation Complex
- Recruits Chromatin modifying complex; histone acetylatin and H3K4 methylation
- Open chromsome at TATAA/Inr
- Allow GTF and PolII acess
Term
Chromatin Modifying Complex
Definition

- Histone Acetylation and H3K4 methylation

 

Term
Transcriptional repressors
Definition
- Bind at RE's at promoter or supressor - Recruit corep complexes like HDACs or H3K9 methylation transferase -H3K9 meth signals HP1 proteins recruitment and form facultative heterchromatin - Non permissive environment
Term
Chromatin modifications
Definition
- Occur at N-terminal tail of histone with high spec
Term
HAT
Definition
- Acetylation at K; activation
- Reversed by deactylation
Term
HDAC
Definition
- Histone deactylases; HDAC
- Transcriptional repression
Term
Methylation
Definition
- two types
- Arg methyl transferases - activation
- Lys methltransferases; activation for set7/9 and rep for g9a
Term
Peptidyl arg deiminases
Definition
- remove methyl amine group from meth arg n histone
- converts metharg to citrulline
Term
Lysine demethylase
Definition
- LSD1 for H3K4 methyl so kills activity
Term
DNA methyltransfersases
Definition
- methylation of DNA
- ex; CpG methylation= gene silencing
Term
CBP/p800
Definition
- Blood cancer and Huntngtons
- Brain and blood diseases
Term
MECP2
Definition
- CpG binding protein2, binds methylated promoter recruits HDAC
- Rett syndrome
Term
HDAC Activation
Definition
- HDAC repress the tumor supressor; too much growth
- neoplasm
Term
HDAC inhib
Definition
- Block HDAC, allows expression of tum sup, stop cancer!
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