RAD50 Deficiency and Its Effects on Zebrafish Embryonic Development and DNA Repair Mechanisms

The MRE11-RAD50-NBS1 (MRN) complex is essential in detecting, signaling, and repairing DNA double-strand breaks (DSBs), thus maintaining genomic integrity. Mutations in RAD50 are linked to severe conditions such as microcephaly, mental retardation, and growth retardation in humans. This study investigates the developmental impact of RAD50 protein disruption in zebrafish embryos. Zebrafish embryos were treated with MIRIN (35 µM) to inhibit RAD50 and subsequently exposed to gamma-ray irradiation (15 Gy) to analyze the role of RAD50 in managing DNA damage during embryogenesis. Time-point analysis indicated that inhibiting RAD50 and ATM proteins during early embryonic stages (at 1 hpf) leads to increased embryonic mortality and abnormalities. These adverse effects were exacerbated by irradiation, underscoring the critical role of RAD50 in DNA DSB repair. The study concludes that RAD50 deficiencies can lead to embryonic lethality and human deformities due to the inability of tissues to repair DNA DSBs effectively.