Download Gene Expression

Gene Expression
AKA Molecular Biology
Gene Expression
Le Dogma Centrale
Genome Organization
Gene Structure
Transcription
Post-transcriptional Modification
Translation
Post-translational Modification
Regulatory Sequences
Transcription
• Just 3 little words that aren't that hard to say:
– Initiation
– Elongation
– Termination
RNA Polymerases
RNA Polymerases
Pol I Promoters
Pol I Initiation
Pol II Promoters
Pol II Initiation
Classes of mRNA
• Abundant Class – Simple mRNA Fraction
– 1- 5 different genes (transcripts) which represent >50%
of total mRNA expressed in cell/tissue
– 1,000 - 100,000 copies of each mRNA/cell
• Moderate Class
– 5-50 different genes (transcripts) which represent 1020% of total mRNA expressed in cell/tissue
– 10 -100 copies of each mRNA/cell
• Rare Class – Complex mRNA Fraction
– >100 different genes (usually 10-20K genes) which
represent 10%-20% of the total mRNA expressed in a
cell/tissue
– 1-10 copies of each mRNA/cell
Pol III Promoters
Pol III Initiation
Functional Domains of Eukaryotic
Transcription Factors
• DNA binding domain – DBD
– Binds specific sequence of base pairs
• Transcriptional activation domain – TAD
– Interacts with basal txn factors or directly with
RNA polymerase II
• Protein-protein interaction domain – PPID
– Homo- & Hetero dimerization domains
– Interaction with other txn factors (besides the
basal apparatus)
Transcription Factor Families
Family
Homeodomain
Representative
Hox
POU
LIM
Paired Box
Hoxa-1, Antp, eve, en
Pit-1,Unc-86, Oct-2, Brn-5
Lim-1, Isl-1
Pax-1,2,6, Prd
Forkhead/Winged Helix
Fkh, HNF-3
Basic
leucine-zipper
helix-loop-helix
AP1, Myc, C/EBP
MyoD, Ac, da, emc
Zinc-finger
monomeric
steroid receptors
WT-1, Krox-20, Kr, hb
GR, ER, RAR, kni
Sox
Sry, SoxD, Sox2
MADS box
MEF-1, MCM-1, AG, DEF, SRF
Homeodomain First Identified in Genes
Causing Homeotic Transformations
Antennapedia
Ultrabithorax
Regulation of Gene Specific
Transcription Factors
Regulation of Gene Specific
Transcription Factors
Regulatory Hierarchies