Conservation throughout mammalia and extensive protein-encoding capacity of the highly repeated DNA long interspersed sequence one

Burton, Frank H.; Loeb, Daniel D.; Voliva, Charles F.; Martin, Sandra L.; Edgell, Marshall H.; Hutchison, Clyde A.

doi:10.1016/0022-2836(86)90235-4

Cited by 145 publications

(76 citation statements)

References 33 publications

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“…This VOL. 7,1987 on May 10, 2018 by guest http://mcb.asm.org/ Downloaded from region corresponds to CSI, one of the two regions in the LI element that is most conserved among mammals (5). In retroviruses, this region of the pol ORF is believed to encode an endonuclease (9,48).…”

Section: Resultsmentioning

confidence: 99%

The site-specific ribosomal insertion element type II of Bombyx mori (R2Bm) contains the coding sequence for a reverse transcriptase-like enzyme.

Burke¹,

Calalang²,

Eickbush³

1987

Mol. Cell. Biol.

129

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Two classes of DNA elements interrupt a fraction of the rRNA repeats of Bombyx mon. We have analyzed by genomic blotting and sequence analysis one class of these elements which we have named R2. These elements occupy approximately 9% of the rDNA units of B. mon and appear to be homologous to the type II rDNA insertions detected in Drosophila melanogaster. Approximately 25 copies of R2 exist within the B. mori genome, of which at least 20 are located at a precise location within otherwise typical rDNA units. Nucleotide sequence analysis has revealed that the 4.2-kilobase-pair R2 element has a single large open reading frame, occupying over 82% of the total length of the element. The central region of this 1,151-amino-acid open reading frame shows homology to the reverse transcriptase enzymes found in retroviruses and certain transposable elements. Amino acid homology of this region is highest to the mobile line 1 elements of mammals, followed by the mitochondrial type II introns of fungi, and the pol gene of retroviruses. Less homology exists with transposable elements of D. melanogaster and Saccharomyces cerevisiae. Two additional regions of sequence homology between LI and R2 elements were also found outside the reverse transcriptase region. We suggest that the R2 elements are retrotransposons that are site specific in their insertion into the genome. Such mobility would enable these elements to occupy a small fraction of the rDNA units of B. mori despite their continual elimination from the rDNA locus by sequence turnover.A fraction of the 28S ribosomal genes in several insect species is interrupted by segments of non-rDNA approximately 5 kilobases (kb) in length (see the review by Beckingham [3]). Based on the nucleotide sequences of their junction regions, these insertions have been divided into two classes. Type I elements have been reported in Drosophila virilis (34), D. melanogaster (7, 37), Calliphora erythrocephala (43), and Bombyx mori (12,16). They interrupt the 28S rRNA gene at a location approximately two-thirds of the distance from the 5' end of the gene and are flanked by a 14-base-pair (bp) duplication of rDNA sequences. Type II elements have only been reported in D. melanogaster (7,37) and B. mori (12,16). They interrupt the 28S gene 75 bp upstream of the type I elements and do not contain flanking duplications of rDNA sequences. In D. melanogaster, rDNA units containing either of these elements are transcribed at a significantly lower level than are the remaining rDNA units (20,23,28). To be consistent with the singleletter nomenclature frequently used to describe repetitive or transposable DNA elements and to avoid possible confusion with the type I and II intron sequences of fungal mitochondrial DNAs, we suggest that these elements be referred to as the Ri (type I) and R2 (type II) elements (R referring to rDNA units).Disruption of the large rRNA genes has also been detected in noninsect species. In Ascaris lumbricoides, a 4.5-kb element interrupts a small fraction of the 26S rRNA genes at ...

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Section: Resultsmentioning

confidence: 99%

The site-specific ribosomal insertion element type II of Bombyx mori (R2Bm) contains the coding sequence for a reverse transcriptase-like enzyme.

Burke¹,

Calalang²,

Eickbush³

1987

Mol. Cell. Biol.

129

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“…The structure of the I factor is similar to that of long interspersed nuclear elements (LINEs), (19), which are repeated elements found in a wide range of mammals (10) and in several other eukaryotic species such as Bombyx mon (9,70), trypanasomids (21,31,42), Neurospora crassa (32), and Zea mays (60). They are distinct from other transposable elements in that they lack terminal repeats and have an adenine-rich sequence at the 3' end of the plus strand.…”

mentioning

confidence: 87%

The 5' untranslated region of the I factor, a long interspersed nuclear element-like retrotransposon of Drosophila melanogaster, contains an internal promoter and sequences that regulate expression.

McLean¹,

Bucheton²,

Finnegan³

1993

Mol. Cell. Biol.

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The I-R system of hybrid dysgenesis in Drosophila melanogaster is controlled by a long interspersed nuclear element-like retroposon, the I factor. Transposition of the I factor occurs at a high frequency only in the ovaries of females produced by crossing males of inducer strains that contain functional I factors with females of reactive strains that lack them. In this study, the 5' untranslated region of the I factor was joined to

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“…The classes, population density, and evolution of TEs are varied within eukaryotes. For example, long interspersed elements (L1s) are thought to be transmitted vertically; are the most populous in the mammalian genome, accounting for almost half of the sequences in the mouse and human genomes (41,48,60); and have been demonstrated to have recurrent activity since the diversification of the mammalian clade (12,26,61). Conversely, endogenous retroviruses (ERVs) are believed to result from the integration of exogenous retroviruses into the germ line and consequently have short durations of activity before being inactivated by the host genome (4).…”

mentioning

confidence: 99%

Recent Amplification of the Kangaroo Endogenous Retrovirus, KERV, Limited to the Centromere

Ferreri

Brown

Obergfell

et al. 2011

J Virol

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Mammalian retrotransposons, transposable elements that are processed through an RNA intermediate, are categorized as short interspersed elements (SINEs), long interspersed elements (LINEs), and long terminal repeat (LTR) retroelements, which include endogenous retroviruses. The ability of transposable elements to autonomously amplify led to their initial characterization as selfish or junk DNA; however, it is now known that they may acquire specific cellular functions in a genome and are implicated in host defense mechanisms as well as in genome evolution. Interactions between classes of transposable elements may exert a markedly different and potentially more significant effect on a genome than interactions between members of a single class of transposable elements. We examined the genomic structure and evolution of the kangaroo endogenous retrovirus (KERV) in the marsupial genus Macropus. The complete proviral structure of the kangaroo endogenous retrovirus, phylogenetic relationship among relative retroviruses, and expression of this virus in both Macropus rufogriseus and M. eugenii are presented for the first time. In addition, we show the relative copy number and distribution of the kangaroo endogenous retrovirus in the Macropus genus. Our data indicate that amplification of the kangaroo endogenous retrovirus occurred in a lineage-specific fashion, is restricted to the centromeres, and is not correlated with LINE depletion. Finally, analysis of KERV long terminal repeat sequences using massively parallel sequencing indicates that the recent amplification in M. rufogriseus is likely due to duplications and concerted evolution rather than a high number of independent insertion events.

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Conservation throughout mammalia and extensive protein-encoding capacity of the highly repeated DNA long interspersed sequence one

Cited by 145 publications

References 33 publications

The site-specific ribosomal insertion element type II of Bombyx mori (R2Bm) contains the coding sequence for a reverse transcriptase-like enzyme.

The site-specific ribosomal insertion element type II of Bombyx mori (R2Bm) contains the coding sequence for a reverse transcriptase-like enzyme.

The 5' untranslated region of the I factor, a long interspersed nuclear element-like retrotransposon of Drosophila melanogaster, contains an internal promoter and sequences that regulate expression.

Recent Amplification of the Kangaroo Endogenous Retrovirus, KERV, Limited to the Centromere

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