Initiation of vitellogenesis by blood feeding is essential for egg maturation in ticks.Nutrients derived from the blood meal are utilized by female ticks to synthesize the yolk protein precursor vitellogenin(Vg).Engor...Initiation of vitellogenesis by blood feeding is essential for egg maturation in ticks.Nutrients derived from the blood meal are utilized by female ticks to synthesize the yolk protein precursor vitellogenin(Vg).Engorged Ornithodoros moubata ticks can synthesize Vg whether mated or virgin,thus O.moubata is an excellent model for studying the relative roles of blood feeding and mating in tick vitellogenesis.Injection of rapamycin into engorged O.moubata resulted in a reduction of ovarian growth and yolk accumulation in the oocytes of mated females.OmVg expression in the midgut and fat body and protein concentrations in the hemolymph significantly decreased in mated ticks after injection with rapamycin,indicating that inhibition of the nutrient-sensing target of rapamycin(TOR)pathway disrupts egg maturation at the levels of Vg expression and synthesis.These results suggest that the TOR-signaling pathway induces vitellogenesis in response to nutritional stimulation after a blood meal in O.moubata and is functionally independent of the mating-induced pathway.展开更多
基金supported by Grants-in-Aid 16K08094 to DT from the Japan Society for the Promotion of Science(JSPS),Japan.
文摘Initiation of vitellogenesis by blood feeding is essential for egg maturation in ticks.Nutrients derived from the blood meal are utilized by female ticks to synthesize the yolk protein precursor vitellogenin(Vg).Engorged Ornithodoros moubata ticks can synthesize Vg whether mated or virgin,thus O.moubata is an excellent model for studying the relative roles of blood feeding and mating in tick vitellogenesis.Injection of rapamycin into engorged O.moubata resulted in a reduction of ovarian growth and yolk accumulation in the oocytes of mated females.OmVg expression in the midgut and fat body and protein concentrations in the hemolymph significantly decreased in mated ticks after injection with rapamycin,indicating that inhibition of the nutrient-sensing target of rapamycin(TOR)pathway disrupts egg maturation at the levels of Vg expression and synthesis.These results suggest that the TOR-signaling pathway induces vitellogenesis in response to nutritional stimulation after a blood meal in O.moubata and is functionally independent of the mating-induced pathway.
