The nucleotide sequence of a nodule-specific gene, Nms-25 ofMedicago sativa: its primary evolution via exon-shuffling and retrotransposon-mediated DNA rearrangements
✍ Scribed by Zoltán Végh; Éva Vincze; Rafael Kadirov; Gábor Tóth; György Botond Kiss
- Publisher
- Springer
- Year
- 1990
- Tongue
- English
- Weight
- 866 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0167-4412
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✦ Synopsis
We present the primary structure of a nudule-specific gene, Nms-25 from Medicago sativa L. cultivar Nagysz6n/lsi. Analysis of the nucleotide sequence of Nms-25 revealed that this gene shows all the characteristics of an interrupted plant gene consisting of 13 exons and 12 introns. The promoter region of Nms-25 contains the common promoter elements of plant genes as well as motifs which are supposed to be involved in nodule-specific expression. There are two exon-like sequences in the gene named PE1 and PE2 which are not present in the c D N A clones ofMedicago sativa cultivar Cardinal. Intron 9 carries a retrotransposon-like element, Tms 1, which might be responsible for downstream deletion events in which a heptanucleotide, ATTAGCT, might have been involved. Most of the exons, exept 1, 12 and 13, are similar to each other both in length (54 bp) and sequence (up to 94~o sequence similarity). All exons are interrupted by introns in the same phase (type I). It is suggested that exon-shuffiing based on illegitimate recombination in which the A T T A G C T motif might have played an active role, and retrotransposonmediated D N A rearrangements were the primary events in the molecular evolution of the Nms-25 gene.