Directory
Unlocking sperm chromatin at fertilization requires a dedicated egg thioredoxin in Drosophila.
Nat Commun, 7:13539.
In most animals, the extreme compaction of sperm DNA is achieved after the massive replacement of histones with sperm nuclear basic proteins (SNBPs), such as protamines. In some species, the ultracompact sperm chromatin is stabilized by a network of disulfide bonds connecting cysteine residues present in SNBPs. Studies in mammals have established that the reduction of these disulfide crosslinks at fertilization is required for sperm nuclear decondensation and theformation of the male pronucleus. Here, we show that the Drosophila maternal thioredoxin Deadhead (DHD) is specifically required to unlock sperm chromatin atfertilization. In dhd mutant eggs, the sperm nucleus fails to decondense and thereplacement of SNBPs with maternally-provided histones is severely delayed, thuspreventing the participation of paternal chromosomes in embryo development. We demonstrate that DHD localizes to the sperm nucleus to reduce its disulfide targets and is then rapidly degraded after fertilization.
Document Actions
