Chromatin and gene organization during spermatogenesis and early development An evolutionary perspective

精子发生是导致雄性配子（精子）形成的细胞分化过程。精子细胞的脱氧核糖核酸（DNA）与一组称为精蛋白的高度碱性蛋白质有关。这与身体的其他部分（包括卵子）形成鲜明对比，卵子的DNA与一系列核蛋白相关，如核心组蛋白、连接组蛋白和非组蛋白。在这两种情况下，产生的蛋白质- dna复合物被称为染色质。在精子发生过程中，来自干细胞的染色质组蛋白在成熟精子中被精子特异性组蛋白(H)、蛋白蛋白(P)或蛋白蛋白样蛋白（PL）所取代，它们具有介于H和P之间的中间化学成分。参与这些染色质重排的分子机制尚不清楚。本研究的长期目标是描述和理解精子发生和受精后染色质修饰的结构变化和因素。为了方便起见，我们选择了几种具有高配子水平的无脊椎动物和脊椎动物进行分析。这项研究有双重意义。从应用的角度来看，对这些染色质转变的理解可以启发社会对人类不育问题、精子竞争和其他生物物种形成的认识。从学术的角度来看，对不同生物体中参与这些过程的基因和相应蛋白质的分析和表征，为研究它们的进化提供了一个独特的机会。

Spermatogenesis is a cell differentiation process leading to the formation of the male gametes (spermatozoa). The deoxyribonucleic acid (DNA) of sperm cells is associated with a set of highly basic proteins called protamines. This contrasts with the rest of the body, including eggs, in which the DNA is associated with a broad spectrum of nuclear proteins such as core histones, linker histones and non-histone proteins. In both instances, the resulting protein-DNA complexes are called chromatin.    During spermatogenesis, histones of chromatin from the stem cells are replaced in the mature sperm by sperm-specific histones (H), protamines (P), or protamine-like proteins (PL), which have an intermediate chemical composition between H and P. This histone replacement process reverts during fertilization of the egg by the sperm.    The molecular mechanisms involved in these chromatin rearrangements are poorly understood. The long-term objective of this research is to describe and understand the structural changes and factors involved in the chromatin modifications during spermatogenesis and after fertilization. To facilitate this, we have selected several invertebrate and vertebrate organisms, with high levels of gametes, for analysis.    This research has a two-fold interest. From an applied perspective, the understanding of these chromatin transitions could enlighten society on human infertility problems, sperm competition, and speciation in other organisms. From an academic perspective, the analysis and characterization of the genes and corresponding proteins involved in these processes, in different organisms, provide a unique opportunity to study their evolution.