DNA sequence of the maize transposable element Dissociation

Döring, Hans-Peter; Tillmann, E.; Starlinger, Peter

doi:10.1038/307127a0

Cited by 145 publications

(62 citation statements)

References 18 publications

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“…Composite Ds elements are made of more than one Ds. The only fully sequenced composite Ds is the chromosome breaker element in allele sh-m5933 (9,33). It is composed of two completely identical, simple deletion Ds elements in reverse orientation and of the 8-bp host duplication which flanks the internal element.…”

Section: Resultsmentioning

confidence: 99%

“…There are six fully sequenced Ds elements, all of which share with Ac nearly identical TIRs and fall into the following four categories: (i) those with nearly no similarity to Ac, like Ds1 (57); (ii) elements with highly similar subterminal regions but with internal deletions, like Ds9 (46); (iii) double Ds elements where one internally deleted Ds is inserted into another identical Ds in an inverted orientation (9); and (iv) Ds elements that contain both deletions and insertions in the internal part of the element, like Ds2 (40) and the Ds element in WxB4 (60). While double Ds elements can be interpreted as transposition of one element within the other (9), the mechanism of formation of other types of Ds elements is not known.…”

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confidence: 99%

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Abortive Gap Repair: Underlying Mechanism for Ds element Formation

Rubin

Levy

1997

Molecular and Cellular Biology

114

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The mechanism by which the maize autonomous Ac transposable element gives rise to nonautonomous Ds elements is largely unknown. Sequence analysis of native maize Ds elements indicates a complex chimeric structure formed through deletions of Ac sequences with or without insertions of Ac-unrelated sequence blocks. These blocks are often flanked by short stretches of reshuffled and duplicated Ac sequences. To better understand the mechanism leading to Ds formation, we designed an assay for detecting alterations in Ac using transgenic tobacco plants carrying a single copy of Ac. We found frequent de novo alterations in Ac which were excision rather than sequence dependent, occurring within Ac but not within an almost identical Ds element and not within a stable transposase-producing gene. The de novo DNA rearrangements consisted of internal deletions with breakpoints usually occurring at short repeats and, in some cases, of duplication of Ac sequences or insertion of Ac-unrelated fragments. The ancient maize Ds elements and the young Ds elements in transgenic tobacco showed similar rearrangements, suggesting that Ac-Ds elements evolve rapidly, more so than stable genes, through deletions, duplications, and reshuffling of their own sequences and through capturing of unrelated sequences. The data presented here suggest that abortive Ac-induced gap repair, through the synthesis-dependent strand-annealing pathway, is the underlying mechanism for Ds element formation.Dissociation, or Ds, is the first discovered transposable element (TE). It was identified as a maize locus on chromosome 9, where breaks occur in the presence of Activator (Ac), a second gene found at a separate locus (33,34). Subsequent studies showed that Ac can transpose autonomously whereas Ds moves only in the presence of Ac (35,36). In addition, Ac activity can turn into a Ds type of instability, while no occurrences were found of Ds turning into Ac (37, 38). On the basis of these observations, McClintock proposed that Ds nonautonomous elements are derived from Ac through mutations (39). The proposal that Ac and Ds are phylogenetically related has been supported by molecular analysis, as described below, but the mechanism responsible for the conversion of Ac into Ds is still unknown.Ac is a 4.6-kb-long element flanked by 11-bp terminal inverted repeats (TIRs) (12). It encodes an 807-amino-acid protein, the transposase, necessary for both Ac and Ds transposition (28). Ds elements, on the other hand, do not encode a functional transposase but retain regions which are essential for their transposition (6). There are six fully sequenced Ds elements, all of which share with Ac nearly identical TIRs and fall into the following four categories: (i) those with nearly no similarity to Ac, like Ds1 (57); (ii) elements with highly similar subterminal regions but with internal deletions, like Ds9 (46); (iii) double Ds elements where one internally deleted Ds is inserted into another identical Ds in an inverted orientation (9); and (iv) Ds elements that contain bot...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Abortive Gap Repair: Underlying Mechanism for Ds element Formation

Rubin

Levy

1997

Molecular and Cellular Biology

114

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“…The integration of excised Ds::HPT elements into the rice genome was demonstrated by analyzing Ds::HPT sequences in the hygromycin-resistant caUi which were obtained by culturing transfected protoplasts. In one-third of the resistant calli, the integration of excised Ds::HPTwas found and 8 bp direct repeats, which are produced as a consequence of duplication of a target site upon integration of Ac/Ds (D6ring et aL, 1984;Pohlman et aL, 1984;Sutton et aL, 1984), flanked the integrated Ds::HPT. The analysis of the empty target site sequence clearly showed that 8 bp direct repeats were produced upon integration of Ds::HPT.…”

Section: Discussionmentioning

confidence: 99%

“…Eight base pair direct repeats flank the Ds in five out of six calli. Because Ac/Ds elements induce duplication of a target site of 8 bp upon integration (D6ring et al, 1984;Pohlman et al, 1984;Sutton et aL, 1984), the 8 bp direct repeats observed here were likely to have been generated upon integration of Ds::HPT. This was verified by analyzing the integration site in untransformed rice DNA ( Figure 5).…”

Section: Transformation Of Rice Protoplasts By Ds::h Ptmentioning

confidence: 94%

Transposition of the maize Ds element from a viral vector to the rice genome

Sugimoto

Otsuki²,

Saji³

et al. 1994

The Plant Journal

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SummaryThe geminivirus miecanthus streak virus (MiSV) was used as a gene vector to study the transposition of the maize D$ element in rice protoplasts. Efficient excision of the Ds from the MiSV vector was observed only when the MiSV vector was allowed to replicate and the plasmid expressing the transposese gene encoded by Ac was co-transfected. Under the same condition, the Ds carrying a hygromycin phosphotransfersse gene (Ds::HPT) was also efficiently excised. Hygromycin-rasistant calli were obtained by culturing these transfected protoplasts in order to examine the transpmdtion of the excimKI Ds::HPTinto the rice genome. In five out of 16 calli examined, the Ds::HPT, but not the vector sequence, was integrated into the rice genome and 8 bp target site duplication typical of AciDs transposition was generated. These results show that the D$::HPT inserted in the MiSV vector transposed directly into the rice genome. This demonstrates the direct transposition of s cloned plant transposable element into the plant genome. Implications of these finding are discussed.

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“…Sequence analysis of the Ds-r deletion derivative trDs-228 showed the breakpoints of the deletion to be at small direct repeats. Also, Ac-derived Ds elements like Ds2 [18], Ds6 [22], Ds9 [44] and AcA [47] and deletion derivatives of the Drosophila P element [41] have small direct repeats at breakpoints. The mechanism which was used to explain the P deletion derivatives is 'double-strand gap repair' [24].…”

Section: The Generation Of Ds-r Deletion Derivativesmentioning

confidence: 99%

Transposition pattern of a modified Ds element in tomato

et al. 1993

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Several aspects of transposition of an in vitro modified Ds element are described. This Ds element, designated Ds-r, is equipped with bacterial plasmid sequences and can, therefore, be rescued from the plant genome. Our results indicate that the Ds-r element has a 'late' timing of transposition from T-DNAs. This feature of the element might be advantageous for tagging experiments because it leads to independently transposed germinally transmitted elements. Furthermore, it is shown that Ds-r transposition generates clusters of insertions, indicating that 'genes to be tagged' should be located in genomic regions covered by insertions.

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DNA sequence of the maize transposable element Dissociation

Cited by 145 publications

References 18 publications

Abortive Gap Repair: Underlying Mechanism for Ds element Formation

Abortive Gap Repair: Underlying Mechanism for Ds element Formation

Transposition of the maize Ds element from a viral vector to the rice genome

Transposition pattern of a modified Ds element in tomato

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