Bxb1

Bxb1 bacteriophage was isolated in the Bronx, NY [1]. It infects Mycobacterium Smegmatis. Its genome is around 50.000 bp and code for 86 proteins [1]. Bxb1 integrase catalyze integration of the phage genome into the GroEL1 gene of M.segmentis, which contains the attB site [2]. Minimal attB, attP,[2],[3] attL and attR [4] have been characterized. Excisionase has been identified, is relatively big (28kDa) for a RDF, and is efficient both in vivo and in vitro [4]. In vitro recombination is very efficient ranging a 100% efficiency in 1hour for integration [2] and for excision [4]. Interestingly the excisionase subunit does not bind DNA and acts stoechiometrically on Bxb1 integrase [4]. The enzyme does not require supercoiled DNA, and can also works with linear products [2]. The enzyme also works well in human, rat, and mouse cells [5, 6].

Uniprot entry:

Bxb1 integrase Bxb1 excisionase

• att sites:

From

attP:

attB:

attL:

attR:

References:

[1] Genome organization and characterization of mycobacteriophage Bxb1., mediavilla et al., Mol microbiol, 2000. PMID 1123671.

[2] Mycobacteriophage Bxb1 integrates into the Mycobacterium smegmatis groEL1 gene. Kim AI, Ghosh P, Aaron MA, Bibb LA, Jain S, Hatfull GF. Mol Microbiol. 2003

[3] The orientation of mycobacteriophage Bxb1 integration is solely dependent on the central dinucleotide of attP and attB. Ghosh P, Kim AI, Hatfull GF. Mol Cell. 2003 PMID:14636570

[4] Control of phage Bxb1 excision by a novel recombination directionality factor., Ghosh P. et al, PLoS Biol., 2006. PMID: 16719562.

[5] Phage Bxb1 integrase mediates highly efficient site-specific recombination in mammalian cells., Russel JP et al., Biotechniques, 2006. PMID:16629393

[6] A diversity of serine phage integrases mediate site-specific recombination in mammalian cells. Keravala A, Groth AC, Jarrahian S, Thyagarajan B, Hoyt JJ, Kirby PJ, Calos MP. Mol Genet Genomics, 2006 PMID: 16699779