Molecular characterization of clathrin heavy chain (Chc) in Rhipicephalus haemaphysaloides and its effect on vitellogenin (Vg) expression via the clathrin-mediated endocytic pathway.

Clathrin plays an important role in arthropods, but its function in ticks has not been explored. Here, we describe the molecular characteristics of the clathrin heavy chain of the tick Rhipicephalus haemaphysaloides and its effects on yolk development. The open reading frame of the clathrin heavy chain (Chc) (Rh-Chc) gene consists of 5103 nucleotides encoding 670 amino acids, which is most closely related to that of Ixodes scapularis and relatively close to Homo sapiens and Drosophila melanogaster. Real-time qPCR revealed that Rh-Chc was expressed at all developmental stages and organs. After Rh-Chc is silenced, ticks did not feed and mortality rate was 100%. Moreover, Rh-Chc co-localized with Vitellogenin receptor (VgR) on oocyte membrane. Immunofluorescence showed that the expression of Vitellogenin (Vg) (Rh-Vg) was also closely related to Rh-Chc. Immunofluorescence showed that the expression of Vg was also closely related to Rh-Chc, Rh-Chc silencing slowed the development of oocytes in tick, and culture of ovary in vitro silenced Rh-Chc, the development of oocytes in ticks also slowed down. Overall, the results of this study indicated that Rh-Chc is a vital gene in the tick R. haemaphysaloides that plays an important role in its growth, development, and reproduction.