A functional analysis of chromatin reorganisation during sperm morphogenesis in Drosophila

在哺乳动物中，精子发生过程中的染色质重塑导致精子中单倍体基因组的极度浓缩状态，从核小体结构转变为基于鱼精蛋白的甜甜圈结构。受精后和合子形成前，父系基因组发生重组以恢复核小体结构。我们对果蝇的这一过程知之甚少，因此我们研究了组蛋白的位移和降解，以及转化蛋白和蛋白在果蝇精子发生中的可能作用。GFP标记的染色质蛋白版本是跟踪体内染色质重组的极好工具，例如使用携带H2a-GFP的非组蛋白蝇株。我们开始研究组蛋白降解的机制是否依赖于睾丸中存在的泛素结合酶。作为暂态染色体蛋白的候选物，我们分析了Don Juan， Don Juan like和CG1988。我们通过egpf标记的版本显示了在精子发生结束时染色质中存在鱼精蛋白样e分子。这种方法和功能方法，如筛选各自基因的突变，异位表达研究和蛋白质分析，将有助于了解整个基因组的染色质重组，这是男性生育能力所需要的。

Chromatin remodelling during spermiogenesis leads to an extreme condensed state of the haploid genome in the sperm by a switch from the nucleosomal configuration to a protamine based doughnut structure in mammals. After fertilization and before zygote formation a reorganization of the paternal genome takes place to resume the nucleosomal configuration. Not much is known about this process in Drosophila, therefore we address questions of the displacement and degradation of histones, the possible role of tran sition proteins and protamines in an in vivo context in Drosophila spermiogenesis. GFP tagged versions of chromatin proteins are an excellent tool to follow chromatin reorganisation in vivo, such as the use of ahistone H2a-GFP carrying fly strain. We began to study if the mechanism of histone degradation is dependent on ubiquitin-conjugating enzymes present in the testes. As candidates for transient chromosomal proteins we analyse Don Juan, Don Juan like and CG1988. We showed the presence of a protamine lik e molecule in the chromatin at the end of spermiogenesis by an eGPF-tagged version. This and functional approaches, like screening for mutants in the respective genes, ectopic expression studies and protein analysis, will help to understand chromatin reorganization of the entire genome, needed for male fertility.