Antagonistic conflict between transposon-encoded introns and guide RNAs

• 成果类型: Article
• 署名作者: Zedaveinyte, Rimante; Meers, Chance; Le, Hoang C.; Mortman, Edan E.; Tang, Stephen; Lampe, George D.; Pesari, Sanjana R.; Gelsinger, Diego R.; Wiegand, Tanner; Sternberg, Samuel H.
• 署名单位: Columbia University; Columbia University; University of California System; University of California San Diego
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-13063
• DOI: 10.1126/science.adm8189
• 发表日期: 2024-07-12
• 关键词: group-i introns; multiple sequence alignment; clostridium-difficile; central dinucleotide; crystal-structure; bxb1 integration; dna transposons; read alignment; istron cdist1; bacterial

摘要

TnpB nucleases represent the evolutionary precursors to CRISPR-Cas12 and are widespread in all domains of life. IS605-family TnpB homologs function as programmable RNA-guided homing endonucleases in bacteria, driving transposon maintenance through DNA double-strand break-stimulated homologous recombination. In this work, we uncovered molecular mechanisms of the transposition life cycle of IS607-family elements that, notably, also encode group I introns. We identified specific features for a candidate IStron from Clostridium botulinum that allow the element to carefully control the relative levels of spliced products versus functional guide RNAs. Our results suggest that IStron transcripts evolved an ability to balance competing and mutually exclusive activities that promote selfish transposon spread while limiting adverse fitness costs on the host. Collectively, this work highlights molecular innovation in the multifunctional utility of transposon-encoded noncoding RNAs.