African swine fever virus encodes a gene with extensive homology to type II DNA topoisomerases

Topoisomerase II from Chlorella Virus PBCV-1 Has an Exceptionally High DNA Cleavage Activity

“…Consequently, it is rare that they encode their own DNA topoisomerases. Nonetheless, poxviruses encode a type I topoisomerase (7)(8)(9)(10), and three other viruses, African swine fever virus (21,22), P. bursaria Chlorella virus (23), and Chilo iridescent virus (24), contain open reading frames that are predicted to encode type II topoisomerases. One common feature of these viruses is that they have large double-stranded DNA genomes, ranging from 170 kb in African swine fever virus (69) to 330 kb in PBCV-1 (70).…”

“…However, open reading frames predicted to encode type II topoisomerases recently have been reported in three eukaryotic viral genomes: the asfarvirus African swine fever virus (21,22), the phycodnavirus Paramecium bursaria Chlorella virus (PBCV-1) 1 (23), and the iridovirus Chilo iridescent virus (24). Of these viruses, the only one that has been demonstrated to encode an active topoisomerase II is PBCV-1 (25).…”

Nucleotide sequence of a 55 kbp region from the right end of the genome of a pathogenic African swine fever virus isolate (Malawi LIL20/1)

“…1). DNA inserts from these plasmid subclones, from bacteriophage lambda clones LMw22 and LMw23, from two previously described plasmid subclones which contain a 4.1 kbp SalI-BamHI fragment from LMwl6 (Hammond et al, 1992) and a 3-5 kbp HindIII fragment from LMw32 (pij 3.5H) (Baylis et al, 1992) and a 700 bp PCR fragment which contained sequences between the 9.5 kbp BamHI-SmaI and 15.9 kbp Sail fragments, were isolated, randomly sheared by sonication and cloned into M13 vectors. Single-stranded DNA was sequenced using dideoxynucleoside triphosphates, [~-3~S]dATP and Klenow enzyme (Bankier et al, 1987) or T7 DNA polymerase.…”

“…Sequences reported include the cross-linked termini and TIRs (Gonz~ilez et al, 1986;Vifiuela, 1987), several genes encoding enzymes such as the large and small subunits of ribonucleotide reductase (Boursnell et al, 1991), thymidine kinase Hernandez & Tabarrs, 1991), thymidylate kinase (Y~ifiez et aL, 1993b), DNA ligase (Hammond et al, 1992;Y~ifiez & Vifiuela, 1993), a ubiquitin-conjugating (UBC) enzyme (Hingamp et al, 1992;Rodrfguez et al, 1992), a serine protein kinase (Baylis et al, 1993a), three putative helicases (Baylis et al, 1993b), three RNA polymerase subunits Y~ifiez et al, 1993a), DNA topoisomerase type II (Baylis et al, 1992;Garcia-Beato et al, 1992), a protein with homology to transcription factor SII (TFSII; Rodriguez et al, 1992), and several genes encoding virus structural proteins and a virus attachment protein (L6pez-Otin et al, 1988(L6pez-Otin et al, , 1990Camacho & Vifiuela, 1991 ;Sim6n-Mateo et al, 1993), one gene with homology to bcl-2 and the Epstein-Barr virus gene BHFR1 (Neilan et aL, 1993) and one gene with homology to CD2 (Rodriguez et al, 1993). In addition two multigene families have been sequenced within variable length regions of the genome close to both left and right termini Gonz~ilez et al, 1990) and one region containing a variable number tandem repeat array has been sequenced (Dixon et al, 1990a).…”

Characterization of Mimivirus DNA Topoisomerase IB Suggests Horizontal Gene Transfer between Eukaryal Viruses and Bacteria

“…The type II topoisomerase of bacteriophage T4 was discovered in 1979 (22,34). Type II topoisomerases have since been identified in the proteomes of eukaryotic viruses, including African swine fever virus (2,10), Paramecium bursaria Chlorella virus (8,9,21), and Emiliana huxleyi Coccolithovirus (39). Unlike most free-living organisms, which have multiple topoisomerases from at least two of the major families, it appeared that viruses acquired no more than one topoisomerase in aid of their replication.…”