Protocol for systematic screening of histone H3/H4 mutants to identify histone residues critical for BCAA-dependent replicative lifespan

Here, we present a protocol for high-throughput replicative lifespan (RLS) screening in Saccharomyces cerevisiae using micromanipulation-based aging assays with growth phenotyping. We describe steps for preparing yeast strains, isolating virgin cells, and monitoring divisions to calculate lifespan changes in histone H3/H4 mutants. We also describe sulfometuron methyl (SM) spotting assay to evaluate growth phenotypes linked to branched-chain amino acid (BCAA) metabolism, enabling identification of residues critical for lifespan regulation. For complete details on the use and execution of this protocol, please refer to Park et al.¹.