Sequence, assembly and analysis of pX01 and pX02

Abstract

. Bacillus anthracis plasmids pX01 and pX02, harboured by the Sterne and Pasteur strains, respectively, have been sequenced by random 'shotgun' cloning and high throughout sequence analysis. These sequences have been assembled (Sequencher) to generate a circulate pX01 plasmid containing 181 656 bp and a single linear (gapped) pX02 contig containing at least 93·479 bp. Initial annotation suggests that the two plasmids combined contain at least 200 potential open reading frames (ORFs) with ³ 40% having significant similarity to sequences registered in open databases. Collectively, only 118 566 bp of the pX01 DNA (65%) represent predicted coding regions. This value is similar to published gene densities for other plasmids and is indicative of the larger intergenic spaces in plasmids vs those found in the chromosomes of the parental microbes (85-93% gene density). A 70 kbp region including the toxin genes (cya, lef and pag) is distinct from the remainder of the pX01 sequence: (1) it has a lower gene density (58 vs 70%) than the remaining 111 kbp; (2) it contains all but one of the co-regulated transcriptional fusions identified by transposon mutagenesis (Hoffmaster and Koehler 1997) and (3) it contains a significantly higher proportion of positive BLAST scores (62 vs 20%) for putative ORFs. These data suggest different origins for the two regions of pX01.

Identification of a transposable genomic island of Paracoccus pantotrophus DSM 11072 by its transposition to a novel entrapment vector pMMB2

“…However, in the case of TnPpa1, transposition is responsible for the movement of the element. The same mechanism of translocation is also suggested for a 44?8 kb long pathogenicity island of Bacillus anthracis which is flanked by inverted copies of IS1627 (Okinaka et al, 1999).…”

Comparative analysis of two-component signal transduction systems of Bacillus cereus, Bacillus thuringiensis and Bacillus anthracis

“…Since main differences between members of the B. cereus group have been attributed to their plasmids (Okinaka et al, 1999;Rasko et al, 2005;Schnepf et al, 1998), the DNA of 29 B. cereus group plasmids was also scanned for genes encoding TCSs. Surprisingly, only plasmid pBc10987 of B. cereus ATCC 10987 appeared to encode a TCS, while one 'orphan' RR was found on the megaplasmid pE33L466 of B. cereus ZK (results not shown).…”

“…Members of the B. cereus group form a highly homogeneous subdivision within the genus Bacillus and it has been proposed that B. cereus, B. thuringiensis and B. anthracis are in fact varieties of the same species (Daffonchio et al, 2000;Helgason et al, 2000). However, B. anthracis and B. thuringiensis differ from B. cereus by containing plasmid-encoded specific toxins and a capsule (B. anthracis only) (Okinaka et al, 1999;Schnepf et al, 1998) and recent studies have shown that B. anthracis is rather monomorphic, whereas there is large diversity within B. cereus and B. thuringiensis (Bavykin et al, 2004;Hill et al, 2004;Priest et al, 2004).…”

Identification of anthrax toxin genes in aBacillus cereusassociated with an illness resembling inhalation anthrax

“…In contrast, B. anthracis is the etiologic agent of anthrax, an acute fatal disease among mammals, which in recent years has become known for its use as a biological weapon (6). The genes encoding the major anthrax toxins and the poly-␥-D-glutamic acid capsule are located on two virulence plasmids, pXO1 (182 kb) and pXO2 (96 kb), respectively, and are required for full virulence (7)(8)(9).…”