Hazzouri M, Rousseaux S, Mongelard F, Usson Y, Pelletier R, Faure A K, Vourc'h C, Sèle B
Unité INSERM U309, UJF, Institut Albert Bonniot, Faculté de Médecine de Grenoble, Domaine de la Merci, La Tronche, France.
Mol Reprod Dev. 2000 Mar;55(3):307-15. doi: 10.1002/(SICI)1098-2795(200003)55:3<307::AID-MRD9>3.0.CO;2-P.
The sperm nucleus has a unique chromatin structure where the DNA is highly condensed and associated with specific proteins, the protamines. It is a nondividing cell which is also transcriptionally inactive. After fusion with an oocyte, the sperm nucleus undergoes decondensation and, in the same time, starts replication and transcription. It has been suggested that somatic chromosomes during interphase are organized in territories which display a cell type and cell cycle specific distribution. The purpose of this work was to investigate whether chromosomes would also have a specific distribution in the sperm nucleus, which could be related to its inactive state, and have implications on the early stages of fertilization. In the present study, centromeric and telomeric sequences were detected by fluorescent techniques performed on human decondensed spermatozoa. Chromosome painting probes were used to detect the chromosome X and chromosome 13 on interphase sperm nuclei. The fluorescent signals were captured in 3D with a confocal microscope. For each of these chromatin structures, the volume, position, and distribution of the signals were analyzed in samples of 30 nuclei with the help of image analysis software. The centromeres appeared grouped in several foci that were randomly distributed within the sperm nucleus. The telomeres gave an approximately haploid number of small signals, evenly distributed throughout the nucleus. The chromosomes X and 13 occupied 4.7% and 3. 7% of the total nuclear volume, respectively. Interestingly, the X chromosome territory showed a preferential position in the anterior half of the volume of the nucleus, whereas chromosome 13 had a random position. This work shows a particular distribution of chromosome territories in the human sperm nucleus that could be related to mechanisms implicated in its specific functions. The analysis of more chromosomes and chromosomal structures, including the Y chromosome, would help to understand the structure of the human sperm chromatin, and its fundamental and clinical implications.
精子细胞核具有独特的染色质结构，其中DNA高度浓缩并与特定蛋白质——鱼精蛋白相关联。它是一个不进行分裂的细胞，转录也不活跃。与卵母细胞融合后，精子细胞核发生解聚，同时开始复制和转录。有人提出，间期的体细胞染色体在区域中进行组织，这些区域呈现出细胞类型和细胞周期特异性分布。这项工作的目的是研究染色体在精子细胞核中是否也有特定分布，这可能与其不活跃状态相关，并对受精早期阶段有影响。在本研究中，通过对人类解聚精子进行荧光技术检测着丝粒和端粒序列。使用染色体涂染探针检测间期精子细胞核上的X染色体和13号染色体。用共聚焦显微镜以三维方式捕获荧光信号。对于这些染色质结构中的每一种，借助图像分析软件在30个细胞核的样本中分析信号的体积、位置和分布。着丝粒呈现为聚集在几个焦点中，这些焦点在精子细胞核内随机分布。端粒给出大约单倍体数量的小信号，均匀分布在整个细胞核中。X染色体和13号染色体分别占总核体积的4.7%和3.7%。有趣的是，X染色体区域在细胞核体积的前半部分显示出优先位置，而13号染色体位置随机。这项工作表明人类精子细胞核中染色体区域存在特定分布，这可能与涉及其特定功能的机制有关。对更多染色体和染色体结构（包括Y染色体）的分析将有助于理解人类精子染色质的结构及其基本和临床意义。
