Short-term sequence evolution and vertical inheritance of the Naegleria twin-ribozyme group I intron
Journal article, Peer reviewed
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Original versionWikmark, O.-G., Einvik, C., De Jonckheere, J.F. & Johansen, S.D. (2006). Short-term sequence evolution and vertical inheritance of the Naegleria twin-ribozyme group I intron. BMC Evolutionary Biology, 6: 39. doi: 10.1186/1471-2148-6-39
Ribosomal DNA of several species of the free-living Naegleria amoeba harbors an optional group I intron within the nuclear small subunit ribosomal RNA gene. The intron (Nae.S516) has a complex organization of two ribozyme domains (NaGIR1 and NaGIR2) and a homing endonuclease gene (NaHEG). NaGIR2 is responsible for intron excision, exon ligation, and full-length intron RNA circularization, reactions typical for nuclear group I intron ribozymes. NaGIR1, however, is essential for NaHEG expression by generating the 5' end of the homing endonuclease messenger RNA. Interestingly, this unusual class of ribozyme adds a lariat-cap at the mRNA.