Julius B. Lucks/Bibliography/Ham-BiotechBioengineering-94-2006

= Notes on Ham-BiotechBioengineering-94-2006 =


 * fim inversion in E. coli - unidirectional switch
 * expression system - arabinose inducible fimE, and fim invertible DNA segment containing constitutively active promoter
 * target gene has promoter in OFF orientation (no transcribed product)
 * add arabinose, fimE flips DNA sequence, turning promoter in ON position causing transcription of target gene
 * tightly controlled basal expression, highly inducible
 * large scale expression of toxic proteins
 * Other inducible systems
 * IPTG induced trc (P_trc)
 * arabinose induced araBAD (P_BAD)
 * Podhajska 1985 - inversion-based expression system using lambda Int and attP/attB Podhajska-Gene-40-1985
 * tight control when not intuced, and high induction level when induced - (Sektas, 2001)
 * requires heat-shock induction mechanism
 * type I fimbrae in E. coli has phase variation
 * due to inversion of 314-bp segment containing promoter of fimA by invertases FimB and FimE (Klemm, 1986)
 * FimB inverts both directions, FimE inverts preferrentially ON to OFF
 * invertases bind to non-identical inverted repeats surrounding invertible DNA segment
 * 'sequences between promoter and RBS could form mRNA secondary structures that could aversly affect expression' - (de Smit and van Duin 1994, Pfleger 2005)
 * arabinose induces once to start gene expression - no need for extra inducer - can use a pulse of arabinose


 * flipase memory system
 * diagram attP/B push system

= References =


 * 1) Julius B. Lucks/Bibliography