Site-specific recombination

Site-specific recombination, also known as conservative site-specific recombination, is a type of genetic recombination in which DNA strand exchange takes place between segments possessing at least a certain degree of sequence homology.[1][2][3] Enzymes known as site-specific recombinases (SSRs) perform rearrangements of DNA segments by recognizing and binding to short, specific DNA sequences (sites), at which they cleave the DNA backbone, exchange the two DNA helices involved, and rejoin the DNA strands. In some cases the presence of a recombinase enzyme and the recombination sites is sufficient for the reaction to proceed; in other systems a number of accessory proteins and/or accessory sites are required. Many different genome modification strategies, among these recombinase-mediated cassette exchange (RMCE), an advanced approach for the targeted introduction of transcription units into predetermined genomic loci, rely on SSRs.

Site-specific recombination systems are highly specific, fast, and efficient, even when faced with complex eukaryotic genomes.[4] They are employed naturally in a variety of cellular processes, including bacterial genome replication, differentiation and pathogenesis, and movement of mobile genetic elements.[5] For the same reasons, they present a potential basis for the development of genetic engineering tools.[6]

Recombination sites are typically between 30 and 200 nucleotides in length and consist of two motifs with a partial inverted-repeat symmetry, to which the recombinase binds, and which flank a central crossover sequence at which the recombination takes place. The pairs of sites between which the recombination occurs are usually identical, but there are exceptions (e.g. attP and attB of λ integrase).[7]

  1. ^ Bode, J; Schlake, T; asadasasada Iber, M; Schuebeler, D; Seibler, J; Snezhkov, E; Nikolaev, L (2000). "The transgeneticist's toolbox: novel methods for the targeted modification of eukaryotic genomes". Biol. Chem. 381 (9–10): 801–813. doi:10.1515/BC.2000.103. PMID 11076013. S2CID 36479502.
  2. ^ Kolb, A.F. (2002). "Genome Engineering Using Site-Specific Recombinases". Cloning & Stem Cells. 4 (1): 65–80. doi:10.1089/153623002753632066. PMID 12006158.
  3. ^ Coates, C.J.; Kaminski, JM; Summers, JB; Segal, DJ; Miller, AD; Kolb, AF (2005). "Site-directed genome modification: derivatives of BAL-modifying enzymes as targeting tools" (PDF). Trends in Biotechnology. 23 (8): 407–19. doi:10.1016/j.tibtech.2005.06.009. PMID 15993503. Archived from the original (PDF) on 2006-08-29.
  4. ^ Sauer, B. (1998). "Inducible Gene Targeting in Mice Using the Cre/loxSystem" (PDF). Methods. 14 (4): 381–92. doi:10.1006/meth.1998.0593. PMID 9608509. Archived from the original (PDF) on 2011-06-11.
  5. ^ Nash, H. A. (1996). Site-specific recombination: integration, excision, resolution, and inversion of defined DNA segments. Escherichia coli and Salmonella: cellular and molecular biology, 2, pp. 2363–2376.
  6. ^ Akopian, A.; Stark, W.M. (2005). Site-Specific DNA Recombinases as Instruments for Genomic Surgery. Advances in Genetics. Vol. 55. pp. 1–23. doi:10.1016/S0065-2660(05)55001-6. ISBN 978-0-12-017655-7. PMID 16291210.
  7. ^ Landy, A. (1989). "Dynamic, Structural, and Regulatory Aspects of lambda Site-Specific Recombination". Annual Review of Biochemistry. 58 (1): 913–41. doi:10.1146/annurev.bi.58.070189.004405. PMID 2528323.