A novel family of tyrosine integrases encoded by the temperate pleolipovirus SNJ2. Issue 5 (18th January 2018)

• Record Type: Journal Article
• Authors: Wang, Jiao; Liu, Yingchun; Liu, Ying; Du, Kaixin; Xu, Shuqi; Wang, Yuchen; Krupovic, Mart; Chen, Xiangdong
• Is Part Of: Nucleic acids research. Volume 46:Issue 5(2018)
• Page Start: 2521
• Page End: 2536
• Publication Date: 2018-01-18
• Subjects: Nucleic acids -- Periodicals; Molecular biology -- Periodicals; 572.805
• DOI: 10.1093/nar/gky005
• Languages: English
• ISSNs: 0305-1048

Abstract

Abstract: Genomes of halophilic archaea typically contain multiple loci of integrated mobile genetic elements (MGEs). Despite the abundance of these elements, however, mechanisms underlying their site-specific integration and excision have not been investigated. Here, we identified and characterized a novel recombination system encoded by the temperate pleolipovirus SNJ2, which infects haloarchaeon Natrinema sp. J7-1. SNJ2 genome is inserted into the tRNA Met gene and flanked by 14 bp direct repeats corresponding to attachment core sites. We showed that SNJ2 encodes an integrase (Int SNJ2 ) that excises the proviral genome from its host cell chromosome, but requires two small accessory proteins, Orf2 and Orf3, for integration. These proteins were co-transcribed with Int SNJ2 to form an operon. Homology searches showed that Int SNJ2 -type integrases are widespread in haloarchaeal genomes and are associated with various integrated MGEs. Importantly, we confirmed that SNJ2-like recombination systems are encoded by haloarchaea from three different genera and are critical for integration and excision. Finally, phylogenetic analysis suggested that Int SNJ2 -type recombinases belong to a novel family of archaeal integrases distinct from previously characterized recombinases, including those from the archaeal SSV- and pNOB8-type families.