The retrotransposon R2 maintains Drosophila ribosomal DNA repeats.

ABSTRACT: Ribosomal DNA (rDNA) loci contain hundreds of tandemly repeated copies of ribosomal RNA genes needed to support cellular viability. This repetitiveness makes it highly susceptible to copy number (CN) loss due to intrachromatid recombination between rDNA copies, threatening multigenerational maintenance of rDNA. How this threat is counteracted to avoid extinction of the lineage has remained unclear. Here, we show that the rDNA-specific retrotransposon R2 is essential for restorative rDNA CN expansion to maintain rDNA loci in the Drosophila male germline. The depletion of R2 led to defective rDNA CN maintenance, causing a decline in fecundity over generations and eventual extinction. We find that double-stranded DNA breaks created by the R2 endonuclease, a feature of R2's rDNA-specific retro

SUBMITTER: Nelson JO 

PROVIDER: S-EPMC10266012 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature