title: En/Spm-like transposons in Poaceae species: transposase sequence variability and chromosomal distribution.
abstract: Belonging to Class II of transposable elements, En/Spm transposons are widespread in a variety of distantly related plant species. Here, we report on the sequence conservation of the transposase region from sequence analyses of En/Spm-like transposons from Poaceae species, namely Zingeria biebersteiniana, Zingeria trichopoda, Triticum monococcum, Triticum urartu, Hordeum spontaneum, and Aegilops speltoides. The transposase region of En/Spm-like transposons was cloned, sequenced, and compared with equivalent regions of Oryza and Arabidopsis from the gene bank database. Southern blot analysis indicated that the En/Spm transposon was present in low (Hordeum spontaneum, Triticum monococcum, Triticum urartu) through medium (Zingeria bieberstiana, Zingeria trichopoda) to relatively high (Aegilops speltoides) copy numbers in Poaceae species. A cytogenetic analysis of the chromosomal distribution of En/Spm transposons revealed the concurence of the chromosomal localization of the En/Spm clusters with mobile clusters of rDNA. An analysis of En/Spm-like transposase amino acid sequences was carried out to investigate sequence divergence between 5 genera--Triticum, Aegilops, Zingeria, Oryza and Arabidopsis. A distance matrix was generated; apparently, En/Spm-like transposase sequences shared the highest sequence homology intra-generically and, as expected, these sequences were significantly diverged from those of O. sativa and A. thaliana. A sequence comparison of En/Spm-like transposase coding regions defined that the intra-genomic complex of En/Spm-like transposons could be viewed as relatively independent, vertically transmitted, and permanently active systems inside higher plant genomes. The sequence data from this article was deposited in the EMBL/GenBank Data Libraries under the accession nos. AY707995-AY707996-AY707997-AY707998-AY707999-AY708000-AY708001-AY708002-AY708003-AY708004-AY708005-AY708005-AY265312.
authors.affiliation: Institute of Evolution, University of Haifa, Mt. Carmel, Haifa, Israel. ahu@gmbae.tubitak.gov.tr
authors.forename: Ahu
authors.initials: A
authors.lastname: Altinkut
authors.forename: Olga
authors.initials: O
authors.lastname: Raskina
authors.forename: Eviatar
authors.initials: E
authors.lastname: Nevo
authors.forename: Alexander
authors.initials: A
authors.lastname: Belyayev
mesh_terms: D000595:Amino Acid Sequence; D015139:Blotting, Southern; D016386:Chromosome Walking; D032461:Chromosomes, Plant / Q000235:genetics*; D004251:DNA Transposable Elements / Q000235:genetics*; D019143:Evolution, Molecular; D018745:Genome, Plant / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D010802:Phylogeny; D006109:Poaceae / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D019895:Transposases / Q000737:chemistry / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D019895:Transposases