DNA sequence Organization and repeat sequences

Britten, Roy J.

doi:10.1007/978-94-010-9160-2_2

Cited by 4 publications

(4 citation statements)

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“…Modularity analogous to that found for the TU elements has been described for certain transposable elements of procaryotes (for example, see reference 34). Such modularity, together with the variable structural arrangements observed for the separate domains of the TU elements, suggests a possible role for these elements in the dispersion and rearrangement of genomic DNA sequences; thus, the TU element may be implicated in the generation of the DNA sequence diversity known to exist even among closely related sea urchin species (6,7,13).…”

Section: Discussionsupporting

confidence: 54%

TU elements: a heterogeneous family of modularly structured eucaryotic transposons.

Hoffman-Liebermann¹,

Liebermann²,

Kedes³

et al. 1985

Mol. Cell. Biol.

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We describe here a family of foldback transposons found in the genome of the higher eucaryote, the sea urchin Strongylocentrotus purpuratus. Two major classes of TU elements have been identified by analysis of genomic DNA and TU element clones. One class consists of largely similar elements with long terminal inverted repeats (IVRs) containing outer and inner domains and sharing a common middle segment that can undergo deletions. Some of these elements contain insertions. The second class is highly heterogeneous, with many different middle segments nonhomologous to those of the first-class and variable-sized inverted repeats that contain only an outer domain. The middle and insertion segments of both classes carry sequences that also are found unassociated from the inverted repeats at many other genomic locations. We conclude that the TU elements are modular structures composed of inverted repeats plus other sequence domains that are themselves members of different families of dispersed repetitive sequences. Such modular elements may have a role in the dispersion and rearrangement of genomic DNA segments.Transposable genetic elements, which were first discovered in maize (41) and later found in bacteria (for a review, see reference 32), have been identified in a variety of animal species (52). There is increasing evidence that transposable elements may play an important role in generating genetic diversity (16). Moreover, in yeast cells, the regulation of the mating-type cassette switch involves site-specific recombinational events similar to those mediated by transposons (24, 31), as does the mechanism regulating the variant expression of surface antigens in trypanosomes (5). In Drosophila melanogaster, hybrid dysgenesis involves the P transposable element (30). Similar rearrangements have been postulated to play a role in the regulation of cell type determination and differentiation (26,42). Recent themselves members of different families of dispersed repetitive sequences. The modularity of the TU element family is reminiscent of the structure of some procaryotic transposons (34) and suggests a possible role for these elements in the dispersion and rearrangement of segments of genomic DNA. MATERIALS AND METHODSGeneral methods. Restriction enzymes were obtained from New England Biolabs or Bethesda Research Laboratories and used according to the instructions of the manufacturers. DNA fragments were isolated by electroelution from either agarose or acrylamide preparative gels after fractionation of the appropriately digested DNA. Further purification by multiple phenol, phenol-chloroform, and chloroform extractions was followed by precipitation with ethanol and resuspension in a small volume (50 to 100 ,ul) of doubly distilled water. Fragments used as hybridization probes were radioactively labeled by nick translation (48). Both acrylamide and agarose gels were run in TBE buffer (0.089 M Tris-borate [pH 8.3], 20 mM EDTA). Fragments of k HindlIl-and pBR322 HinfI-digested DNA were used as molecular weight standar...

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Section: Discussionsupporting

confidence: 54%

TU elements: a heterogeneous family of modularly structured eucaryotic transposons.

Hoffman-Liebermann¹,

Liebermann²,

Kedes³

et al. 1985

Mol. Cell. Biol.

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“…4; unpublished data). Potentially, the TU elements may be able to disperse and amplify other sequences in the genome, thus contributing to genetic diversity among sea urchin species (5,6,10).…”

Section: Fig 6 (A)mentioning

confidence: 99%

“…Sequence comparisons revealed that repeated sequence motifs similar to those making up the 15-base-pair direct repeat unit of the IVR-OD domain of the TU elements exist in the IVRs of transposons identffied in Drosophila melanogaster and maize and in the transcription control regions of certain eucaryotic viral and cellular genes. The remarkable evolutionary conservation of IVR-OD homologs may reflect a biological role for these sequences in DNA transposition, the regulation of gene expression, or both.Transposable genetic elements have been shown to be widespread in the biological world (see reference 49 for a review; 3, 13, 14, 45, 55) where they can affect gene expression (8,28,29,33) and may generate genetic diversity (2,5,6,10,15,16,52). Recently, we reported the discovery of a heterogeneous family of modularly structured transposons, the TU elements, in the genome of the sea urchin Strongylocentrotus purpuratus (31, 24).…”

mentioning

confidence: 99%

“…Transposable genetic elements have been shown to be widespread in the biological world (see reference 49 for a review; 3, 13, 14, 45, 55) where they can affect gene expression (8,28,29,33) and may generate genetic diversity (2,5,6,10,15,16,52). Recently, we reported the discovery of a heterogeneous family of modularly structured transposons, the TU elements, in the genome of the sea urchin Strongylocentrotus purpuratus (31, 24).…”

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confidence: 99%

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Sequences from sea urchin TU transposons are conserved among multiple eucaryotic species, including humans.

Liebermann¹,

Hoffman-Liebermann²,

Troutt³

et al. 1986

Mol. Cell. Biol.

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Sequences homologous to various structural domains of the Strongylocentrotus purpuratus TU family of transposons are present in sea urchin species closely related to S. purpuratus and were found in close proximity to each other in linkage patterns that differed for different species. Sequence homologs of the inverted repeat outer domain (IVR-OD) segment were, in addition, present in a sea urchin related only distantly to S. purpuratus and in all other eucaryotic organisms surveyed. In humans, a polymorphic hybridization pattern was seen for genomic DNA obtained from different individuals. Sequence comparisons revealed that repeated sequence motifs similar to those making up the 15-base-pair direct repeat unit of the IVR-OD domain of the TU elements exist in the IVRs of transposons identffied in Drosophila melanogaster and maize and in the transcription control regions of certain eucaryotic viral and cellular genes. The remarkable evolutionary conservation of IVR-OD homologs may reflect a biological role for these sequences in DNA transposition, the regulation of gene expression, or both.Transposable genetic elements have been shown to be widespread in the biological world (see reference 49 for a review; 3, 13, 14, 45, 55) where they can affect gene expression (8,28,29,33) and may generate genetic diversity (2,5,6,10,15,16,52). Recently, we reported the discovery of a heterogeneous family of modularly structured transposons, the TU elements, in the genome of the sea urchin Strongylocentrotus purpuratus (31, 24). TU1, the initially isolated TU element, consists of an internal (M) segment bracketed by long terminal inverted repeat (IVR) segments; these are divided into structurally distinct inner and outer domains-the latter characterized by a series of tandem repeat units 15 base pairs in length. Other members of the TU element family, which were isolated from an S. purpuratus genomic DNA library on the basis of their homology with the outer domain (OD) of the TUl IVR, include M segments that are not present in TUL. The M segments of TU elements contain sequences that also are found, unassociated with the IVRs, at many other genomic locations. The inclusion of different segments of genomic DNA within different TU elements and the dispersion of TU element sequence domains to multiple locations of the S. purpuratus genome have suggested that these elements may play a role in the rearrangement of genomic DNA segments.The structural heterogeneity of the TU family, the reiterated sequence motif of its IVR-OD segment, and the unique modularity of TU element structure have prompted us to investigate the occurrence of TU-related sequences in the DNAs of other sea urchin species, as well as in other eucaryotes. In this communication, we report that the IVR-OD sequences that define the TU element family in S. purpuratus a) have homologs even in a sea urchin species related only distantly to S. purpuratus (i.e., Lytechinus pictus) and can be found in more closely related sea urchins in close physical proximity to segments ho...

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Sequences From Sea Urchin TU Transposons Are Conserved among Multiple Eucaryotic Species, Including Humans

Liebermann

Hoffman-Liebermann

Troutt

et al. 1986

Molecular and Cellular Biology

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DNA sequence Organization and repeat sequences

Cited by 4 publications

References 41 publications

TU elements: a heterogeneous family of modularly structured eucaryotic transposons.

TU elements: a heterogeneous family of modularly structured eucaryotic transposons.

Sequences from sea urchin TU transposons are conserved among multiple eucaryotic species, including humans.

Sequences From Sea Urchin TU Transposons Are Conserved among Multiple Eucaryotic Species, Including Humans

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