Molecular characterization ofVulmar1, a completemarinertransposon of sugar beet and diversity ofmariner- andEn/Spm-like sequences in the genusBeta

Abstract

Transposons of the Tc1-mariner superfamily are widespread in eukaryotic genomes. We have isolated the mariner element Vulmar1 from Beta vulgaris L., which is 3909 bp long and bordered by perfect terminal inverted repeats of 32 bp with homology to terminal inverted repeats of transposons from soybean and rice. According to a characteristic amino acid signature, Vulmar1 can be assigned to the DD39D group of mariner transposons. Vulmar1 is flanked by a 5'-TA-3' target site duplication that is typical for mariner transposons. Southern hybridization revealed that mariner-like copies are highly abundant in Beta species, and sequence analysis of 10 transposase fragments from representative species of the four Beta sections revealed an identity between 34% and 100% after conceptual translation. By fluorescent in situ hybridization, Vulmar1 was detected in distal euchromatin as well as in some intercalary and pericentromeric regions of all B. vulgaris chromosomes. In addition, using PCR, we were able to amplify fragments of the transposase gene of En/Spm-like transposons in the genus Beta. En/Spm-like transposase sequences are highly amplified in four Beta sections and showed a considerable degree of conservation (88.5-100%) at the protein level, while the homology to corresponding regions of En/Spm transposons of other plant species ranges from 49.5% to 62.5%. By fluorescent in situ hybridization, En/Spm-like transposon signals of strong intensity were detected on all chromosomes of B. vulgaris.

A complete physical map of a wild beet (Beta procumbens) translocation in sugar beet

“…The majority of transposable elements from the translocation are copia-and gypsy-like retroelements (Table 4). For the B. vulgaris chromosomes, a dispersed distribution of these elements over all chromosomes was observed Heslop-Harrison et al 1997), except the centromeric regions and the nucleus-organization-regions (NOR) whereas Vulmar1 and Promar52 mariner-like transposons were clustered within euchromatin and within putatively gene-rich regions at the end of the chromosomes (Jacobs et al 2004).…”

“…They included sequences for a putative Mutator-like transposase, a helitron4-element and a hAT superfamily element. Two transposons from BAC123 belong to the TC1/mariner superfamily Vulmar1 and Promar52 which were described by Jacobs et al (2004).…”

Chromosomal mapping of two Mariner-like elements in the grasshopper Abracris flavolineata (Orthoptera: Acrididae) reveals enrichment in euchromatin

“…Among the transposons, the Mariner elements constitute a superfamily of widespread elements and have been observed in several groups of organisms (Langin et al, 1995;Augé-Gouillou et al, 1995;Plasterk et al, 1999;Feschotte & Wessler, 2002;Jacobs et al, 2004;Sinzelle et al, 2006). Mariner elements are approximately 1,300 bp long and are flanked by a terminal inverted repeat (TIR) of 28-32 bp; the element consists of a single intron-less gene that encodes for the transposase, which is responsible for the transposition mechanism, including excision, transfer and DNA strand repair (Lampe et al, 1996;Wicker et al, 2007).…”

Nested Ty3-gypsy retrotransposons of a single Beta procumbens centromere contain a putative chromodomain

“…The large-scale genomic organization of the sugar beet genome has been well studied and numerous dispersed and tandemly repeated sequences have been localized along chromosomes (Schmidt et al 1995;Kubis et al 1998;Dechyeva et al 2003;Jacobs et al 2004;Dechyeva and Schmidt 2006;Menzel et al 2006).…”