ER type I signal peptidase subunit (LmSPC1) is essential for the survival of Locusta migratoria manilensis and affects moulting, feeding, reproduction and embryonic development.
The endoplasmic reticulum type I signal peptidase complex (ER SPC) is a conserved enzyme that cleaves the signal peptides of secretory or membrane preproteins. The deletion of this enzyme leads to the accumulation of uncleaved proteins in biomembranes and cell death. However, the physiological functions of ER SPC in insects are not fully understood. Here, a catalytic subunit gene of ER SPC, LmSPC1, was cloned from Locusta migratoria manilensis and its physiological functions were analysed by RNA interference (RNAi). The LmSPC1 open reading frame encoded a protein of 178 amino acids with all five conserved regions of signal peptidases. RNAi-mediated knockdown of LmSPC1 resulted in high mortality. Sixty-nine per cent of dead nymphs died of abnormal moulting, corresponding to decreased activity of moulting fluid protease. Moreover, insects in the RNAi group experienced a decline in food intake, and a decrease in the secretion of total protein and digestive enzymes from midgut tissues to the midgut lumen. Furthermore, the females produced fewer eggs and eggs with disrupted embryogenesis. These results indicate that LmSPC1 is required for the secretion of secretory proteins, affects physiological functions, including moulting, feeding, reproduction and embryonic development, and is essential for survival. Therefore, LmSPC1 may be a potential target for locust control.
Genetic Engineering Research Center, School of Life Science, Chongqing Engineering Research Center for Fungal Insecticide, The Key Laboratory of Gene Function and Expression Regulation, Chongqing University, Chongqing, China.
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Zhang
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Xia
D000595:Amino Acid Sequence; D000818:Animals; D004068:Digestive System Physiological Phenomena; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D048188:Locusta migratoria / Q000201:enzymology / Q000502:physiology*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D018978:Molting / Q000502:physiology; D034622:RNA Interference; D012098:Reproduction / Q000502:physiology; D012697:Serine Endopeptidases
D008565:Membrane Proteins; D012697:Serine Endopeptidases; C026515:type I signal peptidase
ER type I signal peptidase; Locusta migratoria; RNA interference; pest control; protein secretion; survival