title: Group II intron mobility using nascent strands at DNA replication forks to prime reverse transcription.
abstract: The Lactococcus lactis Ll.LtrB group II intron uses a major retrohoming mechanism in which the excised intron RNA reverse splices into one strand of a DNA target site, while the intron-encoded protein uses a C-terminal DNA endonuclease domain to cleave the opposite strand and then uses the cleaved 3' end as a primer for reverse transcription of the inserted intron RNA. Here, experiments with mutant introns and target sites indicate that Ll.LtrB can retrohome without second-strand cleavage by using a nascent strand at a DNA replication fork as the primer for reverse transcription. This mechanism connecting intron mobility to target DNA replication may be used by group II intron species that encode proteins lacking the C-terminal DNA endonuclease domain and for group II intron retrotransposition to ectopic sites.
authors.affiliation: Institute for Cellular and Molecular Biology, Department of Chemistry and Biochemistry, and Section of Molecular, Genetics and Microbiology, School of Biological Sciences, University ofTexas at Austin, Austin, TX 78712, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhong
authors.forename: Alan M
authors.initials: AM
authors.lastname: Lambowitz
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000096:biosynthesis / Q000235:genetics; D005798:Genes, Bacterial; D007438:Introns; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation; D012326:RNA Splicing; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; C099786:LtrB protein, Lactococcus lactis; D012329:RNA, Bacterial