Nucleolar introns from Physarum flavicomum contain insertion elements that may explain how mobile group I introns gained their open reading frames

Comparison of two group I intron sequences in the nucleolar genome of the myxomycete Physarum flavicomum to their homologs in the closely relatedPhysarum polycephalum revealed insertion-like elements. One of the insertion-like elements consists of two repetitive sequence motifs of 11 and 101 bp in f...

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Bibliographic Details
Published in:	Nucleic acids research Vol. 22; no. 22; pp. 4553 - 4559
Main Authors:	Vader, Anna, Naess, Jørund, Haugli, Kari, Haugli, Finn, Johansen, Steinar
Format:	Journal Article
Language:	English
Published:	England Oxford University Press 11-11-1994
Subjects:	Animals Base Sequence Cell Nucleolus - genetics Cloning, Molecular DNA Transposable Elements - genetics DNA, Fungal - analysis DNA, Ribosomal - analysis Introns - genetics Molecular Sequence Data Myxomycetes Nucleic Acid Conformation Open Reading Frames - genetics Physarum Physarum - genetics Physarum polycephalum Repetitive Sequences, Nucleic Acid - genetics RNA, Fungal - analysis RNA, Fungal - chemistry RNA, Ribosomal - analysis RNA, Ribosomal - chemistry Sequence Alignment Sequence Analysis, DNA
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Summary:	Comparison of two group I intron sequences in the nucleolar genome of the myxomycete Physarum flavicomum to their homologs in the closely relatedPhysarum polycephalum revealed insertion-like elements. One of the insertion-like elements consists of two repetitive sequence motifs of 11 and 101 bp in five and three copies, respectively. The smaller motif, which flanks the larger, resembles a target duplication and indicates a relationship to transposons or retroelements. The insertion-like elements are found in the peripheral loops of the RNA structure; the positions occupied by the ORFs of mobile nucleolar group I introns. The P.flavicomum introns are 1184 and 637 bp in size, located in the large subunit ribosomal RNA gene, and can be folded into group I intron structures at the RNA level. However, the intron 2s from both P.flavicomum and P.polycephalum contain an unusual core region that lacks the P8 segment. None of the introns are able to self-splice in vitro. Southern analysis of different isolates indicates that the introns are not optional in myxomycetes.
Bibliography:	istex:280208A99245DBB25FF111088AFBF11A9F2078F9 ArticleID:22.22.4553 To whom correspondence should be addressed ark:/67375/HXZ-T07PV1W4-T ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2
ISSN:	0305-1048 1362-4962
DOI:	10.1093/nar/22.22.4553