1. Promoters Information about where to start transcription

2. lac operon

3. E. Coli Promoters E. coli has five sigma factors: Sigma 70: Regulate expression of most genes. Sigma 32: Regulate expression of heat shock proteins. Sigma 28: Regulate expression of flagellar operon (involved in cell motion). Sigma 38: Regulate gene expression against external stresses. Sigma 54: Regulate gene expression for nitrogen metabolism.

4. lacZ operon promoter

8. Promoters tell which strand (hence, direction) to transcribe Note there are 6 possible Open Reading Frames (ORFs)

11. Universal (almost) code

12. Wobble pairing (I = Inosine)

14. Ribosome binding sites (sequences) tell ribosomes where to start translation. Consensus, not definite

15. Translation

16. Shine-Dalgarno Motif Ribosome binding site located about 13 bases upstream of AUG start codon SD sequence is: 5’-AGGAGGU-3’ Middle GGAG is more highly conserved Degree of match is positively correlated with translation rate