The replacement of nucleosome core particles by protamine

Abstract

During the process of sperm cell formation (spermatogenesis), there is a dramatic folding of the DNA. This folding compacts the DNA more tightly than in somatic cells, creating a hydrodynamic sperm head and protecting the DNA from damage. To compact the DNA, protamine, a positively charged protein that binds the negatively charged DNA, ultimately replaces the eight histone proteins that wrap the DNA into a nucleosome. Our goal is to study the physics behind the direct replacement of histones by protamine (rather than indirect replacement) in order to shed more light on the compaction process and possible infertility pathways.