ParB2 spreads into the replication origin of <i>V. cholerae</i> chromosome II (chrII).

<p>The origin region has three functional units: <i>incII</i>, <i>oriII</i> and <i>rctB</i>. <i>incII</i> is required for controlling replication, <i>oriII</i> for initiating replication, and <i>rctB</i> for supplying the chrII-specific replication initiator protein, RctB. RctB binds to two kinds of site: the 11- and 12-mers (arrow heads) and 39-mers (black rectangles). The origin also has binding sites for DnaA and IHF, and the two promoters P<i>rctA</i> and P<i>rctB</i>. The <i>rctA</i> locus has a 39-mer and a binding site for ParB2, <i>parS2-B</i>. The bottom panel shows binding of ParB2 (grey profile) and RctB (black profile) in the origin and flanking regions, determined by ChIP-chip using specific antibodies (denoted as α) against the two proteins. The dashed line represents the average signal for ParB2 (1.1±1.1) over the entire genome. The corresponding value for RctB is 1.1±0.9. <i>parS2-A</i> and <i>parS2-C</i> are the nearest neighbors of <i>parS2-B</i>. The error bars here and elsewhere represent one standard deviation.