Wang Fangfang, Gong Haiyan, Zhang Houshuang, Zhou Yongzhi, Cao Jie, Zhou Jinlin
Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
College of Life Science and Food Engineering, Hebei University of Engineering, Hanshan District, Handan, 056038, China.
Parasitol Res. 2019 May;118(5):1363-1370. doi: 10.1007/s00436-019-06258-1. Epub 2019 Mar 19.
Heat shock cognate 70-kDa protein (RH-Hsc70) was identified from a cDNA library synthesized from the sialotranscriptomes of unfed and fed Rhipicephalus haemaphysaloides. The RH-Hsc70 open reading frame is 1950 bp long and encodes a protein that is 649 amino acids in length, with a predicted molecular weight of 71.1 kDa and a theoretical pI of 5.43. RH-Hsc70 exhibits 98% amino acid identity with Hsc70 in Haemaphysalis flava and 83% identity with Hsc70 in arthropods and mammals. RH-Hsc70 was mainly expressed in nymphs and adult ticks, not in larvae. Real-time quantitative PCR analysis indicated that RH-Hsc70 mRNA expression was induced by blood feeding in adult ticks. In addition, RH-Hsc70 gene expression was higher in the ovaries of fed adult ticks than that in the midguts, salivary glands, and fat bodies of unfed or fed adult ticks. RH-Hsc70 gene knockdown inhibited tick blood feeding, significantly decreased tick engorgement rate, and increased tick death rate. These data illustrate the importance of RH-Hsc70 in tick blood feeding and aging, which makes it a promising candidate for the development of anti-tick vaccines.
热休克同源 70 千道尔顿蛋白（RH-Hsc70）是从不吸血和吸血的血红扇头蜱唾液转录组合成的 cDNA 文库中鉴定出来的。RH-Hsc70 的开放阅读框长 1950 碱基对，编码一种长度为 649 个氨基酸的蛋白质，预测分子量为 71.1 千道尔顿，理论 pI 为 5.43。RH-Hsc70 与黄褐血蜱中的 Hsc70 氨基酸同一性为 98%，与节肢动物和哺乳动物中的 Hsc70 同一性为 83%。RH-Hsc70 主要在若蜱和成蜱中表达，而不在幼虫中表达。实时定量 PCR 分析表明，RH-Hsc70 mRNA 表达在成年蜱吸血后被诱导。此外，RH-Hsc70 基因在吸血成年蜱卵巢中的表达高于未吸血或吸血成年蜱的中肠、唾液腺和脂肪体中的表达。RH-Hsc70 基因敲低抑制蜱吸血，显著降低蜱饱血率，并增加蜱死亡率。这些数据说明了 RH-Hsc70 在蜱吸血和老化中的重要性，这使其成为开发抗蜱疫苗的一个有希望的候选者。
