Identification of Rab family genes and functional analyses of LmRab5 and LmRab11A in the development and RNA interference of Locusta migratoria

Abstract

Rab proteins constitute the largest family of small GTPases, which play pivotal roles in intracellular membrane trafficking in all eukaryotes. A number of Rab genes have been identified in eukaryotes; however, very little information about these genes has been reported in insects. In the current study, for the first time we identified and characterized 27 Rab family genes from Locusta migratoria. Phylogenetic analysis and comparison of domain architecture indicated that Rab family genes are highly conserved among insect species. Tissue‐dependent expression profiles indicated that expression of Rab genes was highest in the ovary, except for LmRab3, which was most highly expressed in hemolymph. The biological function of each Rab gene was investigated using RNA interference (RNAi). Double‐stranded RNA targeting each Rab gene was injected into the hemocoel of nymphs and revealed that suppression of two Rab genes (LmRab5 and LmRab11A) caused 100% mortality. In addition, nymphs injected with dsLmRab5 exhibited severe phenotypic defects in the gastric caeca and midgut, while dsLmRab11A arrested the molting process. We then applied the RNAi of RNAi technique to test if silencing either of these two genes would affect the suppression of the lethal giant larvae (LmLgl) reporter gene and found that suppression of LmRab5 diminished the RNAi efficiency of LmLgl, whereas suppression of LmRab11A enhanced RNAi efficiency of LmLgl. These results indicate that Rab genes contribute differently to RNAi efficiency in different tissues. Our study provides a foundation for further functional investigations of Rab genes and their contributions to RNAi efficiency in L. migratoria.

Clathrin‐dependent endocytosis plays a critical role in larval and pupal development, and female oocyte production in the red flour beetle (Tribolium castaneum)

“…[34][35][36] During the last few years, clathirn-dependent endocytosis has also been demonstrated as a predominate pathway for cellular uptake of dsRNA in insects. 13,[37][38][39][40] Nevertheless, our knowledge of the biological aspects of clathirn-dependent endocytosis in insects is highly limited. In this study, we furthered our understanding of the biological importance of four critically important genes involved in clathrin-dependent endocytosis, TcChc, TcAP50, TcVhaSFD, and TcRab7 in T. castaneum.…”

“…In insects, clathrin‐dependent endocytosis has been shown to be an important pathway for viruses to enter the cells 34–36 . During the last few years, clathirn‐dependent endocytosis has also been demonstrated as a predominate pathway for cellular uptake of dsRNA in insects 13,37–40 . Nevertheless, our knowledge of the biological aspects of clathirn‐dependent endocytosis in insects is highly limited.…”

Integrated morphological and transcriptome profiles reveal a highly-developed extrusome system associated to virulence in the notorious fish parasite, Ichthyophthirius multifiliis

“…Rab proteins are commonly associated with the cytoplasmic faces of different organelles and the transport vesicles that connect them, suggesting the possible role of Rabs in extrusome extrusion from I. multifiliis [ 44 ]. In this study, we identified 25 Rabs in I. multifiliis , which is more than that identified in other single-cell organisms, including Trypanosoma bruce (16) and Plasmodium falciparum (11), but almost half of that identified in Tetrahymena thermophila (56) [ 45 ].…”

Increased RNAi Efficiency by dsEGFP-Induced Up-Regulation of Two Core RNAi Pathway Genes (OfDicer2 and OfAgo2) in the Asian Corn Borer (Ostrinia furnacalis)

“…Fire and Craig C. Mello in 1998 [ 3 ]. Previously, a myriad of reports have shown robust and systemic RNAi responses in various insect species belonging to Coleoptera [ 2 , 4 ] and Orthoptera [ 1 , 5 , 6 ]. However, in some insect species of Diptera, Lepidoptera, and Hemiptera, RNAi efficiency appeared very poor [ 7 , 8 , 9 , 10 , 11 ].…”