Gene Expression

1
Gene Expression
DNA
Phenotype
Replication
Transcription
Translation
Gene
Gene expression
Genes control inherited variation via DNA,
RNA and protein
Protein coding gene
2
Transcription
RNA polymerase
reminder RNA contains ribose, phosphate group
and A, C, G and U (not T)
RNA polymerase (from E. coli )
s
Sigma factor
Core
Sigma factor
Core
3
Transcription in Eukaryotes
RNA polymerases RNA polymerase I rRNA (18S,
28S) RNA polymerase II mRNA RNA
polymerase III small RNAs ( tRNA, 5S rRNA,
snRNAs)
Eukaryotic promotors
Regulatory sequences
4
RNA Processing
5
Translation
6
Translation The Players
tRNA Structure
Ribosome Structure
rRNA lsu 2 3 ssu 1
1 Proteins lsu 34
46-48 ssu 21
33
7
The Coding Dictionary
Met
Phe
Ala
8
Proteins and Heredity
1902 Archibald Garrod linked biochemistry and
inheritance
Hereditary information controls chemical
reactions (in the body)
9
Review Translation
Translation the formation of a protein,
directed by an mRNA in association with ribosomes
Players ribosomes, mRNA, tRNAs, translation
factors
Three stages of translation ?Initiation -
Recruitment of mRNA to the ribosome ?Elongation -
Synthesis of nacent polypeptide ?Termination -
Release of polypeptide from the ribosome
Eukaryotes 80S 40S and 60S 1 and 3
33 and 49 processed Kozak consensus Many
14 2 2