PMID:23251587

Citation	Li, Z and Carlow, CK (2012) Characterization of transcription factors that regulate the type IV secretion system and riboflavin biosynthesis in Wolbachia of Brugia malayi. PLoS ONE 7:e51597
Abstract	The human filarial parasite Brugia malayi harbors an endosymbiotic bacterium Wolbachia (wBm) that is required for parasite survival. Consequently, targeting wBm is a promising approach for anti-filarial drug development. The Type IV secretion system (T4SS) plays an important role in bacteria-host interactions and is under stringent regulation by transcription factors. In wBm, most T4SS genes are contained in two operons. We show the wBm is active since the essential assembly factor virB8-1, is transcribed in adult worms and larval stages, and VirB8-1 is present in parasite lysates. We also identify two transcription factors (wBmxR1 and wBmxR2) that bind to the promoter region of several genes of the T4SS. Gel shift assays show binding of wBmxR1 to regions upstream of the virB9-2 and wBmxR2 genes, whereas wBmxR2 binds to virB4-2 and wBmxR1 promoter regions. Interestingly, both transcription factors bind to the promoter of the ribA gene that precedes virB8-1, the first gene in operon 1 of the wBm T4SS. RT-PCR reveals ribA and virB8-1 genes are co-transcribed as one operon, indicating the ribA gene and T4SS operon 1 are co-regulated by both wBmxR1 and wBmxR2. RibA encodes a bi-functional enzyme that catalyzes two essential steps in riboflavin (Vitamin B2) biosynthesis. Importantly, the riboflavin pathway is absent in B. malayi. We demonstrate the pathway is functional in wBm, and observe vitamin B2 supplementation partially rescues filarial parasites treated with doxycycline, indicating Wolbachia may supply the essential vitamin to its worm host. This is the first characterization of a transcription factor(s) from wBm and first report of co-regulation of genes of the T4SS and riboflavin biosynthesis pathway. In addition, our results demonstrate a requirement of vitamin B2 for worm health and fertility, and imply a nutritional role of the symbiont for the filarial parasite host.
Links	PubMed PMC3518464 Online version:10.1371/journal.pone.0051597
Keywords
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
WOLTR:Q5GSQ0	enables	GO:0044212: transcription regulatory region DNA binding	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
WOLTR:Q5GSQ0		GO:0044212: transcription regulatory region DNA binding	ECO:0000314:		F		Fig.4A "In electrophoretic mobility shift assays (EMSA), FAM-labeled DNA probes derived from the upstream region of ribA, virB8-1, virB3, virB4-2, virB8-2, virB9-2, sodA, wBmxR1 and wBmxR2, and were incubated with (+) or without (–) protein and loaded onto a 6% DNA retardation gel." "(EMSA) showed wBmxR1 binds to regions upstream of the virB9-2, ribA, sodA and wBmxR2 genes (Fig. 4A, C)"	complete CACAO 8150
WOLTR:Q5GSD8		GO:0044212: transcription regulatory region DNA binding	ECO:0000314:		F		Fig.4B "In electrophoretic mobility shift assays (EMSA), FAM-labeled DNA probes derived from the upstream region of ribA, virB8-1, virB3, virB4-2, virB8-2, virB9-2, sodA, wBmxR1 and wBmxR2, and were incubated with (+) or without (–) protein and loaded onto a 6% DNA retardation gel. " "(EMSA) showed ... wBmxR2 binds to virB4-2, ribA, and the wBmxR1 promoter regions (Fig. 4B, C)"	complete CACAO 8151
WOLTR:Q5GSD8	enables	GO:0044212: transcription regulatory region DNA binding	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete

References

See Help:References for how to manage references in GONUTS.