Blood feeding tightly regulates the reproductive cycles in ticks. Vitellogenesis and nutritional signaling are a key event in the tick reproductive cycle. Here we report the identification of a Haemaphysalis longicornis GATA factor, (HlGATA), which is synthesized after a blood meal and acts as a transcriptional activator of vitellogenin (Vg). HlGATA shares structural similarity with other GATA factors of invertebrates and vertebrates. Tick GATA mRNA accumulated in the fat body and midgut prior to blood feeding. However, translation of GATA was activated by blood feeding because the GATA protein increased dramatically in engorged females. RNA interference (RNAi)-mediated knock down of GATA transcript resulted in a significant inhibition of Vg expression and effectively disrupts egg development after blood meal in engorged tick. In addition, HlGATA translation was inhibited by RNAi-mediated knock down of S6 kinase. These experiments have revealed that the GATA factor, which is the specific transcriptional activator of Vg gene, represents important molecule for tick reproduction.

• Damdinsuren Boldbaatar(Laboratory of Emerging Infectious Diseases, Department of Frontier Veterinary Medicine, Kagoshima University, Japan)
• Banzragch Battur(Laboratory of Emerging Infectious Diseases, Department of Frontier Veterinary Medicine, Kagoshima University, Japan)
• Rika Umemiya-Shirafuji(Laboratory of Emerging Infectious Diseases, Department of Frontier Veterinary Medicine, Kagoshima University, Japan)
• Min Liao(Laboratory of Emerging Infectious Diseases, Department of Frontier Veterinary Medicine, Kagoshima University, Japan)
• Tetsuya Tanaka(Laboratory of Emerging Infectious Diseases, Department of Frontier Veterinary Medicine, Kagoshima University, Japan)
• Kozo Fujisaki(Laboratory of Emerging Infectious Diseases, Department of Frontier Veterinary Medicine, Kagoshima University, Japan)