@article{Böhringer2025,
title = {A G-protein coupled receptor is involved in the DUOX pathway in Tribolium castaneum},
author = {AC Böhringer and CC Constanze and M Burghaus and H Merzendorfer},
year = {2025},
date = {2025-03-31},
journal = {Insect Biochem. Mol. Biol.},
pages = {in press},
abstract = {Activation of the dual oxidase (DUOX) pathway is an important intestinal defense mechanism against enteric infection triggering the formation of radical oxygen species by stimulating DUOX enzyme activity and/or gene expression. In insects, several studies have suggested that uracil released by pathogenic bacteria functions as a major trigger molecule for the activation of DUOX, which leads to the formation of antimicrobial hypochlorous acid (HOCl). While the recognition of pathogen-associated molecular patterns of microbes by pattern recognition receptors is well understood, the detection of uracil is still elusive. It has been postulated that a G-protein coupled receptor (GPCR) binds the pyrimidine uracil, which activates PLCβ signalling and further downstream events. So far, no pyrimidinergic receptor has been identified in insects, particularly none that binds uracil nucleotides or sugar derivatives. To identify potential candidates for insect pyrimidine receptors, we used a human P2Y4 receptor as a template to screen the Tribolium castaneum reference proteome. Four promising receptor candidates were identified, of which two were analyzed using RNA interference to determine their influence on uracil-induced TcDUOX expression, HOCl formation and development in control larvae and larvae that were challenged with the enteric pathogen Bacillus thuringiensis. Silencing TcGPCR41 resulted in a loss of uracil-induced TcDUOX expression and HOCl formation. Furthermore, the development of challenged larvae was affected in a manner like that observed in a TcDUOX knockdown. We conclude that the identified receptor may play a role in the uracil-dependent activation of the DUOX-pathways.},
keywords = {RNA interference, Tribolium castaneum},
pubstate = {published},
tppubtype = {article}
}

@article{GAO2022103865,
title = {Both LmDicer-1 and two LmDicer-2s participate in siRNA-mediated RNAi pathway and contribute to high gene silencing efficiency in Locusta migratoria},
author = {Lu Gao and Yanli Wang and Mureed Abbas and Tingting Zhang and Enbo Ma and Hans Merzendorfer and Kun Yan Zhu and Jianzhen Zhang},
url = {https://www.sciencedirect.com/science/article/pii/S0965174822001473},
doi = {https://doi.org/10.1016/j.ibmb.2022.103865},
issn = {0965-1748},
year = {2022},
date = {2022-11-01},
journal = {Insect Biochemistry and Molecular Biology},
pages = {103865},
abstract = {Dicers belong to a class of large RNase III multidomain ribonucleases and are central components of the RNA interference (RNAi) pathways. In insects, Dicer-2 has been known to cleave long double-stranded RNA (dsRNA) in small interfering RNA (siRNA)-mediated-RNAi pathway. However, Dicer-1 is responsible for cleaving precursor microRNAs (pre28 miRNAs) in miRNA-mediated RNAi pathway. In this study, we identified one LmDicer-1 and two LmDicer-2 (LmDicer-2a and LmDicer-2b) genes in Locusta migratoria. The RNAi of RNAi assay showed that knockdown of each of the Dicer genes reduced RNAi efficiency against a target gene (Lmβ-Tubulin), suggesting that all these genes participated in the siRNA-mediated RNAi pathway. Sequence analyses of the siRNAs generated from dsLmβ-Tubulin after silencing each LmDicer gene showed no significant difference in the pattern of siRNAs mapped to dsLmβ-Tubulin. This result indicated that all the three LmDicers are capable of generating siRNAs from the dsRNA. We then generated recombinant proteins consisting of different domains using Escherichia coli expression system and incubated each recombinant protein with dsLmβ-Tubulin. We found that the recombinant Dicer proteins successfully cleaved dsLmβ-Tubulin. However, LmDicer-2a-R lacking dsRBD domain lost activity, suggesting that dsRBD domain is critical for Dicer function. Furthermore, overexpression of these proteins in Drosophila S2 cells improved RNAi efficiency. Our siRNA affinity chromatography and LC-MS/MS analysis identified LmDicer-2a, LmDicer-2b, LmR2D2, LmAgo2a, LmAgo1, LmStaufen and LmTARBP2 as constituents of RNA-induced silencing complex. Taken together, these data show that both LmDicer-1 and two LmDicer-2s all participate in siRNA-mediated RNAi pathway and likely contribute to high RNAi efficiency in L. migratoria.},
keywords = {Dicer, dsRNA-bing protein, RNA interference, RNAi efficiency, siRNA pathway},
pubstate = {published},
tppubtype = {article}
}

@article{XJ2021,
title = {V-ATPase subunit a is required for survival and midgut development of Locusta migratoria},
author = { XJ Liu and XY Liang and J Guo and XK Shi and H Merzendorfer and KY Zhu and JZ Zhang},
doi = { doi: 10.1111/imb.12738},
year = {2022},
date = {2022-02-01},
journal = {Insect Mol Biol. https://doi.10.1111/imb.12738},
volume = {31},
pages = {60-72},
abstract = {The vacuolar-type H+ -ATPase (V-ATPase) is an ATP-dependent proton pump, which regulates various cellular processes. To date, most functional studies on V-ATPases of insects have focused on subunits of the V1 complex, and there is little information on the VO genes. In this study, two cDNA sequences of LmV-ATPase a were identified in Locusta migratoria. RT-qPCR analysis revealed that LmV-ATPase a1 and LmV-ATPase a2 are differentially expressed in various tissues and developmental stages. Injection of dsRNA for the common region of LmV-ATPase a1 and LmV-ATPase a2 into third-instar nymphs resulted in a significant suppression of LmV-ATPase a. The injected nymphs ceased feeding, lost body weight and finally died at a mortality of 98.6%. Furthermore, aberrations of midgut epithelial cells, the accumulation of electron-lucent vesicles in the cytoplasm, and a partially damaged brush border were observed in dsLmV-ATPase a-injected nymphs using transmission electron microscopy. Especially, the mRNA level of wingles, and notch genes were dramatically down-regulated in the dsLmV-ATPase a-injected nymphs. Taken together, our results suggest that LmV-ATPase a is required for survival and midgut development of L. migratoria. Hence, this gene could be a good target for RNAi-based control against locusts. },
keywords = {RNA interference},
pubstate = {published},
tppubtype = {article}
}