Faculty Opinions recommendation of The retrotransposon R2 maintains Drosophila ribosomal DNA repeats.

2021 ◽  
Author(s):  
Barbara Mellone
Keyword(s):  
Ribosomal Dna ◽  
Dna Repeats

scholarly journals SHPRH as a new player in ribosomal RNA transcription and its potential role in homeostasis of ribosomal DNA repeats

Transcription ◽  
2017 ◽  
Vol 9 (3) ◽  
pp. 190-195 ◽  
Author(s):  
Deokjae Lee ◽  
Jun Hong Park ◽  
Shinseog Kim ◽  
Seon-gyeong Lee ◽  
Kyungjae Myung
Keyword(s):  
Ribosomal Rna ◽  
Ribosomal Dna ◽  
Potential Role ◽  
Dna Repeats ◽  
Rna Transcription

scholarly journals The retrotransposon R2 maintains Drosophila ribosomal DNA repeats

2021 ◽  
Author(s):  
Jonathan O Nelson ◽  
Alyssa Slicko ◽  
Yukiko M Yamashita
Keyword(s):  
Ribosomal Dna ◽  
Copy Number ◽  
Double Strand Breaks ◽  
Copy Number Loss ◽  
Dna Repeats ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Male Germline ◽  
Rdna Loci ◽  
Rdna Copy

Ribosomal RNAs (rRNAs) account for 80-90% of all transcripts in eukaryotic cells. To meet this demand, the ribosomal DNA (rDNA) gene that codes for rRNA is tandemly repeated hundreds of times, comprising rDNA loci on eukaryotic chromosomes. This repetitiveness imposes a challenge to maintaining sufficient copy number due to spontaneous intra-chromatid recombination between repetitive units causing copy number loss. The progressive shrinking of rDNA loci from generation to generation could lead to extinction of the lineage, yet the mechanism(s) to counteract spontaneous copy number loss remained unclear. Here, we show that the rDNA-specific retrotransposon R2 is essential for rDNA copy number (CN) maintenance in the Drosophila male germline, despite the perceived disruptive nature of transposable elements. Depletion of R2 led to defective rDNA CN maintenance in multiple contexts, causing a decline in fecundity over generations and eventual extinction of the lineage. Our data suggests that DNA double strand breaks generated by R2 is the initiating event of rDNA CN expansion, stimulating the repair processes proposed to underlie rDNA CN expansion. This study reveals that retrotransposons can provide a benefit to their hosts, contrary to their reputation as genomic parasitic, which may contribute to their widespread success throughout taxa.

scholarly journals CTCF regulates the local epigenetic state of ribosomal DNA repeats

2010 ◽  
Vol 3 (1) ◽  
pp. 19 ◽  
Author(s):  
Suzanne van de Nobelen ◽  
Manuel Rosa-Garrido ◽  
Joerg Leers ◽  
Helen Heath ◽  
Widia Soochit ◽  
...  
Keyword(s):  
Ribosomal Dna ◽  
Dna Repeats ◽  
Epigenetic State

scholarly journals Intergenic transcripts originating from a subclass of ribosomal DNA repeats silence ribosomal RNA genes in trans

EMBO Reports ◽  
2009 ◽  
Vol 11 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Raffaella Santoro ◽  
Kerstin‐Maike Schmitz ◽  
Juan Sandoval ◽  
Ingrid Grummt
Keyword(s):  
Ribosomal Rna ◽  
Ribosomal Dna ◽  
Ribosomal Rna Genes ◽  
Dna Repeats ◽  
In Trans ◽  
Rna Genes

scholarly journals Rad22Rad52-dependent Repair of Ribosomal DNA Repeats Cleaved by Slx1-Slx4 Endonuclease

2006 ◽  
Vol 17 (4) ◽  
pp. 2081-2090 ◽  
Author(s):  
Stéphane Coulon ◽  
Eishi Noguchi ◽  
Chiaki Noguchi ◽  
Li-Lin Du ◽  
Toru M. Nakamura ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Ribosomal Dna ◽  
Tandem Repeats ◽  
Dna Helicase ◽  
Rdna Locus ◽  
Dominant Negative ◽  
Dna Repeats ◽  
Dominant Negative Form ◽  
Eukaryotic Species ◽  
Negative Form

Slx1 and Slx4 are subunits of a structure-specific DNA endonuclease that is found in Saccharomyces cerevisiae, Schizosaccharomyces pombe, and other eukaryotic species. It is thought to initiate recombination events or process recombination structures that occur during the replication of the tandem repeats of the ribosomal DNA (rDNA) locus. Here, we present evidence that fission yeast Slx1-Slx4 initiates homologous recombination events in the rDNA repeats that are processed by a mechanism that requires Rad22 (Rad52 homologue) but not Rhp51 (Rad51 homologue). Slx1 is required to generate ∼50% of the spontaneous Rad22 DNA repair foci that occur in cycling cells. Most of these foci colocalize with the nucleolus, which contains the rDNA repeats. The increased fork pausing at the replication fork barriers in the rDNA repeats in a strain that lacks Rqh1 DNA helicase is further increased by expression of a dominant negative form of Slx1. These data suggest that Slx1-Slx4 cleaves paused replication forks in the rDNA, leading to Rad22-dependent homologous recombination that is used to maintain rDNA copy number.

scholarly journals Identification of DNA cis Elements Essential for Expansion of Ribosomal DNA Repeats inSaccharomyces cerevisiae

2001 ◽  
Vol 21 (1) ◽  
pp. 136-147 ◽  
Author(s):  
Takehiko Kobayashi ◽  
Masayasu Nomura ◽  
Takashi Horiuchi
Keyword(s):  
Ribosomal Dna ◽  
Tandem Repeats ◽  
Mutational Analysis ◽  
Hot Spot ◽  
Repeat Expansion ◽  
5S Rrna ◽  
Rrna Gene ◽  
Dna Repeats ◽  
Rdna Repeat ◽  
5S Rrna Gene

ABSTRACT Saccharomyces cerevisiae carries ∼150 ribosomal DNA (rDNA) copies in tandem repeats. Each repeat consists of the 35S rRNA gene, the NTS1 spacer, the 5S rRNA gene, and the NTS2 spacer. TheFOB1 gene was previously shown to be required for replication fork block (RFB) activity at the RFB site in NTS1, for recombination hot spot (HOT1) activity, and for rDNA repeat expansion and contraction. We have constructed a strain in which the majority of rDNA repeats are deleted, leaving two copies of rDNA covering the 5S-NTS2-35S region and a single intact NTS1, and whose growth is supported by a helper plasmid carrying, in addition to the 5S rRNA gene, the 35S rRNA coding region fused to the GAL7promoter. This strain carries a fob1 mutation, and an extensive expansion of chromosomal rDNA repeats was demonstrated by introducing the missing FOB1 gene by transformation. Mutational analysis using this system showed that not only the RFB site but also the adjacent ∼400-bp region in NTS1 (together called the EXP region) are required for the FOB1-dependent repeat expansion. This ∼400-bp DNA element is not required for the RFB activity or the HOT1 activity and therefore defines a function unique to rDNA repeat expansion (and presumably contraction) separate from HOT1 and RFB activities.

scholarly journals Sir2 suppresses transcription-mediated displacement of Mcm2-7 replicative helicases at the ribosomal DNA repeats

PLoS Genetics ◽  
2019 ◽  
Vol 15 (5) ◽  
pp. e1008138 ◽  
Author(s):  
Eric J. Foss ◽  
Tonibelle Gatbonton-Schwager ◽  
Adam H. Thiesen ◽  
Erin Taylor ◽  
Rafael Soriano ◽  
...  
Keyword(s):  
Ribosomal Dna ◽  
Dna Repeats
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