Raw Data Genetic Screen TelN Loss of Protection Mutants

Search for TelN residues involved in hairpin telomere protectionWhile TelN is well-characterized for its role in telomere resolution, its ability to protect hairpin telomeres from MR degradation remains poorly understood. Previously, we demonstrated that TelN’s protective function is independent of its ability to resolve hairpins using the TelN Y425F point mutant, which abolishes telomere resolution while maintaining protection. Given this clear functional separation, we sought to determine whether specific amino acid residues are exclusively required for telomere protection. We hypothesized that distinct residues within the TelN protein might contribute specifically to its protective function, for example, by binding directly to Rad50 or Mre11. To systematically identify such residues, we performed a random mutagenesis screen in combination with high-throughput sequencing, carefully optimizing conditions to favor single amino acid modifications that would facilitate a clear interpretation of functional effects. The goal was to identify amino acid positions in the TelN protein that are critical for protecting hairpin DNA ends from nuclease degradation but dispensable for telomere resolution.