A transposon-introduced G-quadruplex motif is selectively retained and constrained to downregulate CYP321A1  

作　　者：Zhongyuan Deng Yuting Zhang Chao Gao Wei Shen Shan Wang Xinzhi Ni Sisi Liu Xianchun Li 

机构地区：[1]School of Agricultural Sciences,Zhengzhou University,Zhengzhou,China [2]Department of Entomology and BIO5 Institute,University of Arizona,Tucson,Az,USA [3]StateKeyLaboratory ofAgricultural Microbiology,Huazhong Agricultural University,Wuhan,China [4]Colle of Science,Huazhong Agricultural University,Wuhan,China [5]USDA-ARS,Crop Genetics and Breeding Research Unit,University of Georgia,Tifton Campus,Titon,GA,USA

出　　处：《Insect Science》2022年第6期1629-1642,共14页昆虫科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.31701791);National Science Foundation of China(NSFC)-Henan Joint major grant(No.U2004206);the State Key Laboratory of Cotton Biology(No.CB2020A06);the USDA National Institute of Food and Agriculture Hatch Project(No.ARZT-1370680-R31-R31-172).

摘　　要：Insects utilize xenobiotic compounds to up-and downregulate cytochrome P450 monooxygenases(P450s)involved in detoxification of toxic xenobiotics including phytochemicals and pesticides.G-quadruplexes(G4)-forming DNA motifs are enriched in the promoter regions of transcription factors and function as cis-acting elements to regulate these genes.Whether and how P450s gain and keep G4 DNA motifs to regulate their expression still remain unexplored.Here,we show that CYP321A1,a xenobiotic-metabolizing P450 from Helicoverpa zea,a polyphagous insect of economic importance,has acquired and preserved a G4 DNA motif by selectively retaining a transposon known as HzIS1-3 that carries this G4 DNA motif in its promoter region.The HzIS1-3 G4 DNA motif acts as a silencer to suppress the constitutive and induced expression of CYP321A1 by plant allelochemicals flavone and xanthotoxin through folding into an intramolecular parallel or hybrid-1 conformation in the absence or presence of K^(+).The G4 ligand N-methylmesoporphyrin IX(NMM)strengthens the silencing effect of HzIS1-3 G4 DNA motif by switching its structure from hybrid-1 to hybrid-2.The enrichment of transposons in P450s and other environment-adaptation genes implies that selective retention of G4 DNA motif-carrying transposons may be the main evolutionary route for these genes to obtain G4 DNA motifs.

关 键 词：DNA secondary structure gene regulation Helicoverpa zea natural selec-tion plantallelochemicals SIGNALINGPATHWAY SILENCER 

分 类 号：Q96[生物学—昆虫学]