The GATE retrotransposon in Drosophila melanogaster: mobility in heterochromatin and aspects of its expression in germline tissues

Kogan, Galina L.; Tulin, Adrian; Aravin, Alexei A.; Abramov, Yu. A.; Kalmykova, Alla; Maisonhaute, Claude; Гвоздев, В. А.

doi:10.1007/s00438-003-0827-1

Cited by 30 publications

(29 citation statements)

References 51 publications

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“…Alternatively, retroposition of nanos can produce this sequence, since the entire CG11779 homologous part of siren is included in the third exon of nanos on the complementary strand ( Figure 6). This is a plausible scenario in the context of the expression pattern: nanos mRNA is localized in germline cells (e.g., Forbes and Lehmann 1998), where the activity of retrotransposons is generally enhanced (Zhao and Bownes 1998;Kogan et al 2003). Positive associations between the levels of transcription and transposition frequencies in male germline cells has been demonstrated for the copia retrotransposon in D. melanogaster (Pasyukova et al 1997).…”

Section: Discussionmentioning

confidence: 99%

A Novel Chimeric Gene, siren, With Retroposed Promoter Sequence in the Drosophila bipectinata Complex

2005

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Retrotransposons often produce a copy of host genes by their reverse transcriptase activity operating on host gene transcripts. Since transcripts normally do not contain promoter, a retroposed gene copy usually becomes a retropseudogene. However, in Drosophila bipectinata and a closely related species we found a new chimeric gene, whose promoter was likely produced by retroposition. This chimeric gene, named siren, consists of a tandem duplicate of Adh and a retroposed fragment of CG11779 containing the promoter and a partial intron in addition to the first exon. We found that this unusual structure of a retroposed fragment was obtained by retroposition of nanos, which overlaps with CG11779 on the complementary strand. The potential of retroposition to produce a copy of promoter and intron sequences in the context of gene overlapping was demonstrated.

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Section: Discussionmentioning

confidence: 99%

A Novel Chimeric Gene, siren, With Retroposed Promoter Sequence in the Drosophila bipectinata Complex

2005

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“…RNA in Situ Hybridization. RNA in situ hybridization using DIG-labeled strandspecific riboprobes was performed basically as previously described (32). For the synthesis of the mdg1 riboprobe by T7 in vitro transcription, the plasmid containing the cloned PCR fragment of mdg1 retrotransposon (15) was used.…”

Section: Methodsmentioning

confidence: 99%

“…3A). To analyze the specificity of this effect on piRNA silencing, we compared it with that of the piwi 2 -null mutation and with aub, mael, spn-E, and armi mutations affecting the cytoplasmic components of the piRNA machinery, some of which have been shown to be responsible for the activation of a number of transposons tested in our study (16,(32)(33)(34)(35)(36)(37)(38) (Fig. 3A).…”

Section: Piwi Nuclear Localization Is Indispensable For Transposon Simentioning

confidence: 99%

Separation of stem cell maintenance and transposon silencing functions of Piwi protein

Klenov

Sokolova

Yakushev

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

169

165

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Piwi-interacting RNAs (piRNAs) and Piwi proteins have the evolutionarily conserved function of silencing of repetitive genetic elements in germ lines. The founder of the Piwi subfamily, Drosophila nuclear Piwi protein, was also shown to be required for the maintenance of germ-line stem cells (GSCs). Hence, null mutant piwi females exhibit two types of abnormalities, overexpression of transposons and severely underdeveloped ovaries. It remained unknown whether the failure of GSC maintenance is related to transposon derepression or if GSC self-renewal and piRNA silencing are two distinct functions of the Piwi protein. We have revealed a mutation, piwi Nt , removing the nuclear localization signal of the Piwi protein. piwi Nt females retain the ability of GSC self-renewal and a near-normal number of egg chambers in the ovarioles but display a drastic transposable element derepression and nuclear accumulation of their transcripts in the germ line. piwi Nt mutants are sterile most likely because of the disturbance of piRNA-mediated transposon silencing. Analysis of chromatin modifications in the piwi Nt ovaries indicated that Piwi causes chromatin silencing only of certain types of transposons, whereas others are repressed in the nuclei without their chromatin modification. Thus, Piwi nuclear localization that is required for its silencing function is not essential for the maintenance of GSCs. We suggest that the Piwi function in GSC selfrenewal is independent of transposon repression and is normally realized in the cytoplasm of GSC niche cells.oogenesis | short RNA

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“…The silencing abilities of these natural small RNAs are involved in diverse biological processes, such as (i) the regulation of gene expression by translational inhibition (2), (ii) genome organization and chromosome structure mediated by chromatin modification (60, 65), and (iii) defense against viruses and invasive repeated DNAs (64). Several possible triggers for the production of their dsRNA precursors have been identified, including the folding back of inverted repeats (made possible, for instance, by the palindromic organization of the primary miRNAs), the activity of RNA-dependent RNA polymerases (11,13,34,38,57,59), and readthrough antisense transcription of repeated DNA sequences (5, 56).In Drosophila melanogaster, there is increasing evidence that some proteins thought to be involved in RNA-silencing mechanisms are required for the repression of retrotransposable elements (7,22,26,52,53,62). At least one-fourth of all natural small RNAs cloned in Drosophila (6) were homologous to one or another family of repetitive DNA (mostly retroelements).…”

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confidence: 99%

“…In Drosophila melanogaster, there is increasing evidence that some proteins thought to be involved in RNA-silencing mechanisms are required for the repression of retrotransposable elements (7,22,26,52,53,62). At least one-fourth of all natural small RNAs cloned in Drosophila (6) were homologous to one or another family of repetitive DNA (mostly retroelements).…”

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confidence: 99%

A Novel Repeat-Associated Small Interfering RNA-Mediated Silencing Pathway Downregulates Complementary Sense gypsy Transcripts in Somatic Cells of the Drosophila Ovary

Pélisson

Sarot

Payen-Groschêne

et al. 2007

J Virol

132

108

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Replication of the gypsy endogenous retrovirus involves contamination of the female germ line by adjacent somatic tissues. This is prevented by flam, an as-yet-uncloned heterochromatic pericentromeric locus, at the level of transcript accumulation in these somatic ovarian tissues. We tested the effect of a presumptive RNA silencing mechanism on the accumulation of RNAs produced by constructs containing various gypsy sequences and report that the efficiency of silencing is indeed correlated with the amount of complementary RNAs, 25 to 30 nucleotides in length, in the ovary. For instance, while these RNAs were found to display a three-to fivefold excess of the antisense strands, only the transcripts that contain the complementary sense gypsy sequences could be repressed, indicating that they are targeted at the RNA, not DNA, level. Their size and asymmetry in strand polarity are typical of the novel repeat-associated small interfering RNA (rasiRNA)-mediated pathway, recently suspected to prevent the deleterious expression of selfish DNA specifically in the germ line. Unlike microRNAs (but like rasiRNAs and, surprisingly, siRNAs as well), gypsy rasiRNAs are modified at the 3 end. The rasiRNA-associated protein Piwi (but not Aub) is required for gypsy silencing, whereas Dicer-2 (which makes siRNAs) is not. In contrast, piwi, aub, and flam do not appear to affect somatic siRNA-mediated silencing. The amount of gypsy rasiRNAs is genetically determined by the flam locus in a provirus copy number-independent manner and is triggered in the somatic tissues by some pericentromeric provirus(es), which are thereby able to protect the germ line from retroviral invasion.RNA interference (RNAi) is a common reverse-genetics method that can be used to silence genes in most eukaryotes and involves the introduction of double-stranded RNA molecules (dsRNA) that are complementary to the targeted genic sequences (16). This technique takes advantage of well-conserved, natural RNA silencing mechanisms in which RNase III endonucleases (8) cleave dsRNAs into 21-nucleotide (nt) small RNAs, called small interfering RNAs (siRNAs). siRNAs interact with proteins of the Argonaute family to confer sequence specificity to the silencing complex (55).Various naturally occurring siRNA-like molecules have been described in eukaryotes. These include (i) animal microRNAs (miRNAs), the sequences of which can be conserved from worms to humans (29, 40); (ii) scanRNAs in Tetrahymena thermophila (36) and centromeric repeat-originating siRNAs in Schizosaccharomyces pombe (45); and (iii) siRNAs produced by viruses in plants (20), transposons in Caenorhabditis elegans (56) and transposons in protozoa (14, 61). The silencing abilities of these natural small RNAs are involved in diverse biological processes, such as (i) the regulation of gene expression by translational inhibition (2), (ii) genome organization and chromosome structure mediated by chromatin modification (60, 65), and (iii) defense against viruses and invasive repeated DNAs (64). Several possible ...

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The GATE retrotransposon in Drosophila melanogaster: mobility in heterochromatin and aspects of its expression in germline tissues

Cited by 30 publications

References 51 publications

A Novel Chimeric Gene, siren, With Retroposed Promoter Sequence in the Drosophila bipectinata Complex

A Novel Chimeric Gene, siren, With Retroposed Promoter Sequence in the Drosophila bipectinata Complex

Separation of stem cell maintenance and transposon silencing functions of Piwi protein

A Novel Repeat-Associated Small Interfering RNA-Mediated Silencing Pathway Downregulates Complementary Sense gypsy Transcripts in Somatic Cells of the Drosophila Ovary

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