Damon Runyon Researchers

Dr. Chang is studying protamines—short, positively-charged proteins that condense DNA into chromatin and regulate gene expression in sperm nuclei. While eukaryotic cells use histones to package genomes in a way that allows access for transcription and replication, sperm cells must package their genomes more tightly. For this, many animals deploy protamines instead of histones. Despite sharing certain functions with highly conserved histones, protamines have independently arisen in evolution multiple times and are continuing to rapidly evolution. Using Drosophila fruit fly species as a model, Dr. Chang studies how sperm chromatin regulates gene expression and reproductive fitness. Additionally, although protamine expression is typically limited to testes, their misexpression has been observed in many cancers, indicating an opportunity for therapeutic intervention.