Fig. 1

The artificially circularized genome of putative plasmid pWCP. a illustrates Contig O11_A and IS110 transposable element (TE) identified in our assembly. The red rectangles are regions of 100% nucleotide identity between the two contigs. Outward PCR primers were designed to amplify and confirm circularity of the sequence. b–e Gels for PCR tests to confirm a Wolbachia-associated circular genome. To verify the presence of arthropod DNA in our four Culex pipiens samples and the tetracycline-treated (TC) Culex quinquefasciatus samples, we PCR amplified a 708-bp sequence using LCO1490 and HCO2198 primers (b). A 438-bp fragment of the Wolbachia 16S rRNA gene (c), an approximately 1800 bp sequence amplified with the outward primers designed to support circularity of the genome, as illustrated in top panel (d) and a 431-bp of IS110 TE (e) were obtained in wild C. pipiens samples O03-O07-O11-O12 while no amplification was observed in Wolbachia-free samples. NC corresponds to negative control. f illustrates the complete genome. Each arrow represents an open reading frame (ORF). ORFs with no homology to a known function are shown in grey. ParA-like (green), RelBEtoxin–antitoxin operon (blue), and DnaB_C replicative DNA helicase (orange) that is disrupted by the ISWpi12 TE of the IS110 family (purple) are represented by arrows (with an e value < e⁻¹² from an NCBI Conserved Domain or Pfam Search). Black squares represent the location of (1) the variable number tandem repeat (VNTR) and (2) the extragenic palindrome (EP) region