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

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

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)1629-1642
Number of pages14
JournalInsect Science
Issue number6
StatePublished - Dec 2022


  • DNA secondary structure
  • Helicoverpa zea
  • gene regulation
  • natural selection
  • plant allelochemicals
  • signaling pathway
  • silencer

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Agronomy and Crop Science
  • General Biochemistry, Genetics and Molecular Biology
  • Insect Science


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