- Host: Streptomyces lividans
- Action: tyrosine integrase
length:: 613 aa
crystal structure is unknown.
- Target sequence: attB:: has two inverted repeated sequence (core-type) flanking an overlap region (TTG). Minimal attB is 34 bps while minimal attP is 39 bp for e.coli intramolecular integration. attP:: has core-type sites and overlap region, without an arm-type site. --See the schematic sequence of attB and attP at (1-f1). See Groth-2000 for experiment for minimal sequence. --See Thyagarajan-2001 for integration of attB and attP above background/pseudointegration site ~attP in human genome (these could be very cool model experiment!)
Mutation/directed evolution could change specificity to pseudo attP site (HpsA, 44% identity)
Excisionase has not yet been found.
- directed evolution for targeting human's site
- Non-natural host:
- Integration works in E.coli, mammalian and in vitro,
- Mouse embryos Hollis et al 2003
- Bovine fiboblase--Ma et al 2006
- Drosophila--Groth et al 2004
- Aedes aegyptus--Nimmo et al 2006
- Silk worm--Nakayama et al 2006
- cassette exchange: Drosphila --Bateman et al 2006, fission yeast--Thomson et al 2001, mouse embryonic stem cell--Belteki et al 2003
- Xenopus laevis--Allen&Weeks 2005
- chloroplast transformation--Lutz et al 2004
- gene therapy example--table1 for ref-1
- 1Calos MP. The PhiC31 Integrase System for Gene Therapy. Current gene Therapy, 2006, 6, 633-645.