Structural Organization of S516 Group I Introns in Myxomycetes
Permanent lenke
https://hdl.handle.net/10037/27551Dato
2022-05-25Type
Journal articleTidsskriftartikkel
Peer reviewed
Forfatter
Furulund, Betty Martine Normann; Karlsen, Bård Ove; Babiak, Igor; Haugen, Peik; Johansen, Steinar DaaeSammendrag
Group I introns are mobile genetic elements encoding self-splicing ribozymes. Group I
introns in nuclear genes are restricted to ribosomal DNA of eukaryotic microorganisms. For example,
the myxomycetes, which represent a distinct protist phylum with a unique life strategy, are rich in
nucleolar group I introns. We analyzed and compared 75 group I introns at position 516 in the small
subunit ribosomal DNA from diverse and distantly related myxomycete taxa. A consensus secondary
structure revealed a conserved group IC1 ribozyme core, but with a surprising RNA sequence
complexity in the peripheral regions. Five S516 group I introns possess a twintron organization,
where a His-Cys homing endonuclease gene insertion was interrupted by a small spliceosomal
intron. Eleven S516 introns contained direct repeat arrays with varying lengths of the repeated
motif, a varying copy number, and different structural organizations. Phylogenetic analyses of
S516 introns and the corresponding host genes revealed a complex inheritance pattern, with both
vertical and horizontal transfers. Finally, we reconstructed the evolutionary history of S516 nucleolar
group I introns from insertion of mobile-type introns at unoccupied cognate sites, through homing
endonuclease gene degradation and loss, and finally to the complete loss of introns. We conclude
that myxomycete S516 introns represent a family of genetic elements with surprisingly dynamic
structures despite a common function in RNA self-splicing.
Forlag
MDPISitering
Furulund, Karlsen, Babiak, Haugen, Johansen. Structural Organization of S516 Group I Introns in Myxomycetes. Genes. 2022;13(6)Metadata
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