A feedback loop betweenWolbachiaand theDrosophila gurkenmRNP complex influencesWolbachiatiter

Abstract

SummaryAlthough much is known about interactions between bacterial endosymbionts and their hosts, little is known concerning the host factors that influence endosymbiont titer. Wolbachia endosymbionts are globally dispersed throughout most insect species and are the causative agent in filarial nematode-mediated disease. Our investigation indicates that gurken (grk), a host gene encoding a crucial axis determinant, has a cumulative, dosage-sensitive impact on Wolbachia growth and proliferation during Drosophila oogenesis. This effect appears to be mediated by grk mRNA and its protein-binding partners Squid and Hrp48/Hrb27C, implicating the grk mRNA-protein (mRNP) complex as a rate-limiting host factor controlling Wolbachia titer. Furthermore, highly infected flies exhibit defects that match those occurring with disruption of grk mRNPs, such as nurse cell chromatin disruptions and malformation of chorionic appendages. These findings suggest a feedback loop in which Wolbachia interaction with the grk mRNP affects both Wolbachia titer and grk mRNP function.

Unscrambling butterfly oogenesis

“…In D. mauritiana, Wolbachia increases egg production by affecting the maintenance and division of germ-line stem cells [20], while in the wasp Asobara tabida , Wolbachia confers a reproductive advantage to the females by properly regulating apoptosis during oogenesis via its regulation of iron metabolism and ferritin expression [190,192]. However, in D. melanogaster highly infected females suffer from a range of oogenesis defects mediated via grk signalling [193]. Pararge aegeria females were also found to be infected with Wolbachia, but how this affects oogenesis in this species is at present not known.…”

Global Wolbachia prevalence, titer fluctuations and their potential of causing cytoplasmic incompatibilities in tsetse flies and hybrids of Glossina morsitans subgroup species

“…RNAi-knockdown of ColA causes loss of symbiont growth control resulting in disruption of the highly beneficial long-term relationship between host and symbiont (Login et al, 2011). Finally Serbus et al (2011) have demonstrated that Wolbachia -titer in D. melanogaster might be regulated through a feedback loop between the host gene gurken ( grk ) and the symbiont itself. Regarding our finding that Wolbachia -titers increase dramatically in the five Glossina hybrids compared to their non-hybrid mothers, we suggest that strict titer regulation of the symbiont is crucial in that system too.…”

MappingWolbachiadistributions in the adultDrosophilabrain

“…It may be that nutrient levels in the host cells play a key role in influencing titre while Wolbachia surface proteins that interact with specific host factors determine its localization. Support of this notion comes from the close association between Wolbachia and polarity determinants in the Drosophila oocyte (Serbus and Sullivan, 2007;Serbus et al, 2011).…”