RT Journal
A1 Darby, Alistair C.
A1 Armstrong, Stuart D.
A1 Bah, Germanus S.
A1 Kaur, Gaganjot
A1 Hughes, Margaret A.
A1 Kay, Suzanne M.
A1 Koldkjær, Pia
A1 Rainbow, Lucille
A1 Radford, Alan D.
A1 Blaxter, Mark L.
A1 Tanya, Vincent N.
A1 Trees, Alexander J.
A1 Cordaux, Richard
A1 Wastling, Jonathan M.
A1 Makepeace, Benjamin L.
T1 Analysis of gene expression from the Wolbachia genome of a filarial nematode supports both metabolic and defensive roles within the symbiosis
JF Genome Research 
JO Genome Research 
YR 2012 
FD December 01 
VO 22 
IS 12 
SP 2467 
OP 2477 
DO 10.1101/gr.138420.112 
UL http://genome.cshlp.org/content/22/12/2467.abstract 
AB The α-proteobacterium Wolbachia is probably the most prevalent, vertically transmitted symbiont on Earth. In contrast with its wide distribution in arthropods, Wolbachia is restricted to one family of animal-parasitic nematodes, the Onchocercidae. This includes filarial pathogens such as Onchocerca volvulus, the cause of human onchocerciasis, or river blindness. The symbiosis between filariae and Wolbachia is obligate, although the basis of this dependency is not fully understood. Previous studies suggested that Wolbachia may provision metabolites (e.g., haem, riboflavin, and nucleotides) and/or contribute to immune defense. Importantly, Wolbachia is restricted to somatic tissues in adult male worms, whereas females also harbor bacteria in the germline. We sought to characterize the nature of the symbiosis between Wolbachia and O. ochengi, a bovine parasite representing the closest relative of O. volvulus. First, we sequenced the complete genome of Wolbachia strain wOo, which revealed an inability to synthesize riboflavin de novo. Using RNA-seq, we also generated endobacterial transcriptomes from male soma and female germline. In the soma, transcripts for membrane transport and respiration were up-regulated, while the gonad exhibited enrichment for DNA replication and translation. The most abundant Wolbachia proteins, as determined by geLC-MS, included ligands for mammalian Toll-like receptors. Enzymes involved in nucleotide synthesis were dominant among metabolism-related proteins, whereas the haem biosynthetic pathway was poorly represented. We conclude that Wolbachia may have a mitochondrion-like function in the soma, generating ATP for its host. Moreover, the abundance of immunogenic proteins in wOo suggests a role in diverting the immune system toward an ineffective antibacterial response.