Open AccessAging impairs double‐strand break repair by homologous recombination in Drosophila germ cells
Author(s) -
Delabaere Laetitia,
Ertl Henry A.,
Massey Dashiell J.,
Hofley Carolyn M.,
Sohail Faraz,
Bienenstock Elisa J.,
Sebastian Hans,
Chiolo Irene,
LaRocque Jeannine R.
Publication year - 2017
Publication title -
aging cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.103
H-Index - 140
eISSN - 1474-9726
pISSN - 1474-9718
DOI - 10.1111/acel.12556
Subject(s) - rad51 , genome instability , biology , homologous recombination , dna repair , non homologous end joining , germline , microbiology and biotechnology , dna damage , germ cell , genetics , brca2 protein , dna , mutation , germline mutation , gene
Summary Aging is characterized by genome instability, which contributes to cancer formation and cell lethality leading to organismal decline. The high levels of DNA double‐strand breaks ( DSB s) observed in old cells and premature aging syndromes are likely a primary source of genome instability, but the underlying cause of their formation is still unclear. DSB s might result from higher levels of damage or repair defects emerging with advancing age, but repair pathways in old organisms are still poorly understood. Here, we show that premeiotic germline cells of young and old flies have distinct differences in their ability to repair DSB s by the error‐free pathway homologous recombination ( HR ). Repair of DSB s induced by either ionizing radiation ( IR ) or the endonuclease I‐SceI is markedly defective in older flies. This correlates with a remarkable reduction in HR repair measured with the DR ‐white DSB repair reporter assay. Strikingly, most of this repair defect is already present at 8 days of age. Finally, HR defects correlate with increased expression of early HR components and increased recruitment of Rad51 to damage in older organisms. Thus, we propose that the defect in the HR pathway for germ cells in older flies occurs following Rad51 recruitment. These data reveal that DSB repair defects arise early in the aging process and suggest that HR deficiencies are a leading cause of genome instability in germ cells of older animals.