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History of the discovery of a master locus producing piRNAs: the flamenco/COM locus in Drosophila melanogaster.

Goriaux C, Théron E, Brasset E, Vaury C - Front Genet (2014)

Bottom Line: The discovery of flamenco (flam) an heterochromatic locus from Drosophila melanogaster and its ability to survey several TEs such as gypsy, ZAM, and Idefix contributed to peer deeply into the mechanisms of the genetic and epigenetic regulation of TEs. flam was the first cluster producing small RNAs to be discovered long before RNAi pathways were identified in 1998.As a result of the detailed genetic analyses performed by certain laboratories and of the sophisticated genetic tools they developed, this locus has played a major role in our understanding of piRNA mediated TE repression in animals.Here we review the first discovery of this locus and retrace decades of studies that led to our current understanding of the relationship between genomes and their TE targets.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire GReD, Faculté de Médecine, Clermont Université - Université d'Auvergne, Clermont-Ferrand France ; INSERM, U 1103, Clermont-Ferrand France ; CNRS, UMR 6293, Clermont-Ferrand France.

ABSTRACT
The discovery of transposable elements (TEs) in the 1950s by B. McClintock implied the existence of cellular regulatory systems controlling TE activity. The discovery of flamenco (flam) an heterochromatic locus from Drosophila melanogaster and its ability to survey several TEs such as gypsy, ZAM, and Idefix contributed to peer deeply into the mechanisms of the genetic and epigenetic regulation of TEs. flam was the first cluster producing small RNAs to be discovered long before RNAi pathways were identified in 1998. As a result of the detailed genetic analyses performed by certain laboratories and of the sophisticated genetic tools they developed, this locus has played a major role in our understanding of piRNA mediated TE repression in animals. Here we review the first discovery of this locus and retrace decades of studies that led to our current understanding of the relationship between genomes and their TE targets.

No MeSH data available.


Related in: MedlinePlus

Model of TE invasions, silencing, and remobilization.
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Figure 5: Model of TE invasions, silencing, and remobilization.

Mentions: Overall, data obtained on flam fit with a model of TE invasion and its subsequent genomic control as follows (Figure 5). The best genetic background for a TE family to transpose is to enter a virgin genome in which no homologous sequence exists. In such a genome, no regulatory piRNAs are produced that are able to target the new TE. For that reason, horizontal transfer of a TE coming from another species increases the chances that a TE can invade a particular genome. After entering, the newly acquired TE starts replication cycles and its copies insert across the genome. Either by chance, because of relaxed selection, or because of active targeting, a new TE copy will eventually insert into a piRNA cluster. The pool of piRNA precursors produced by this locus will then be changed because of the presence of new sequences brought in by the new TE insertion. These new precursors, transferred to Dot COM and then processed in piRNAs in Yb-bodies will act in trans to silence their homologous copies. When this occurs, genomic stability is recovered. Due to their highly repetitive nature, piRNA clusters may subsequently undergo deletion events removing small or large portions of the locus. These deletions can remove TE sequences and may result in sudden bursts of transposition. Thus, periods of stability and instability in global TE dynamics will reflect the mutational events that affect piRNA clusters.


History of the discovery of a master locus producing piRNAs: the flamenco/COM locus in Drosophila melanogaster.

Goriaux C, Théron E, Brasset E, Vaury C - Front Genet (2014)

Model of TE invasions, silencing, and remobilization.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4120762&req=5

Figure 5: Model of TE invasions, silencing, and remobilization.
Mentions: Overall, data obtained on flam fit with a model of TE invasion and its subsequent genomic control as follows (Figure 5). The best genetic background for a TE family to transpose is to enter a virgin genome in which no homologous sequence exists. In such a genome, no regulatory piRNAs are produced that are able to target the new TE. For that reason, horizontal transfer of a TE coming from another species increases the chances that a TE can invade a particular genome. After entering, the newly acquired TE starts replication cycles and its copies insert across the genome. Either by chance, because of relaxed selection, or because of active targeting, a new TE copy will eventually insert into a piRNA cluster. The pool of piRNA precursors produced by this locus will then be changed because of the presence of new sequences brought in by the new TE insertion. These new precursors, transferred to Dot COM and then processed in piRNAs in Yb-bodies will act in trans to silence their homologous copies. When this occurs, genomic stability is recovered. Due to their highly repetitive nature, piRNA clusters may subsequently undergo deletion events removing small or large portions of the locus. These deletions can remove TE sequences and may result in sudden bursts of transposition. Thus, periods of stability and instability in global TE dynamics will reflect the mutational events that affect piRNA clusters.

Bottom Line: The discovery of flamenco (flam) an heterochromatic locus from Drosophila melanogaster and its ability to survey several TEs such as gypsy, ZAM, and Idefix contributed to peer deeply into the mechanisms of the genetic and epigenetic regulation of TEs. flam was the first cluster producing small RNAs to be discovered long before RNAi pathways were identified in 1998.As a result of the detailed genetic analyses performed by certain laboratories and of the sophisticated genetic tools they developed, this locus has played a major role in our understanding of piRNA mediated TE repression in animals.Here we review the first discovery of this locus and retrace decades of studies that led to our current understanding of the relationship between genomes and their TE targets.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire GReD, Faculté de Médecine, Clermont Université - Université d'Auvergne, Clermont-Ferrand France ; INSERM, U 1103, Clermont-Ferrand France ; CNRS, UMR 6293, Clermont-Ferrand France.

ABSTRACT
The discovery of transposable elements (TEs) in the 1950s by B. McClintock implied the existence of cellular regulatory systems controlling TE activity. The discovery of flamenco (flam) an heterochromatic locus from Drosophila melanogaster and its ability to survey several TEs such as gypsy, ZAM, and Idefix contributed to peer deeply into the mechanisms of the genetic and epigenetic regulation of TEs. flam was the first cluster producing small RNAs to be discovered long before RNAi pathways were identified in 1998. As a result of the detailed genetic analyses performed by certain laboratories and of the sophisticated genetic tools they developed, this locus has played a major role in our understanding of piRNA mediated TE repression in animals. Here we review the first discovery of this locus and retrace decades of studies that led to our current understanding of the relationship between genomes and their TE targets.

No MeSH data available.


Related in: MedlinePlus