RT Journal Article SR Electronic(1) A1 Wang, Yuchen A1 Chen, Beibei A1 Cao, Mengzhuo A1 Sima, Linshan A1 Prangishvili, David A1 Chen, Xiangdong A1 Krupovic, MartYR 2018 T1 Rolling-circle replication initiation protein of haloarchaeal sphaerolipovirus SNJ1 is homologous to bacterial transposases of the IS91 family insertion sequences JF Journal of General Virology, VO 99 IS 3 SP 416 OP 421 DO https://doi.org/10.1099/jgv.0.001009 PB Microbiology Society, SN 1465-2099, AB For most archaeal viruses, the mechanisms of genome replication are poorly understood, while the nature and provenance of their replication proteins are usually unknown. Here we show that replication of the circular double-stranded DNA genome of the halophilic Natrinema virus SNJ1, a member of the family Sphaerolipoviridae, is associated with the accumulation of single-stranded replicative intermediates, which is typical of rolling-circle replication. The homologues of RepA, the only enzyme that is indispensable for SNJ1 genome replication, are widespread in archaea and are most closely related to bacterial transposases of the IS91 and ISCR family insertion sequences, as opposed to other viral rolling-circle replication initiation proteins. Our results provide insights into the replication mechanism of archaeal viruses and emphasize the evolutionary connection between viruses and other types of mobile genetic elements., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.001009