Abstract:
Prophase I is a remarkable stage of meiotic division during which homologous chromosomes pair together and exchange DNA by meiotic recombination. Fluorescence microscopy of meiotic chromosome spreads is a central tool in the study of this process, with chromosome axis proteins being visualized as extended filaments upon which recombination proteins localize in focal patterns.Chromosome pairing and recombination are dynamic processes, and hundreds of recombination foci can be present in some meiotic nuclei. As meiotic nuclei can exhibit significant variations in staining patterns within and between nuclei, particularly in mutants, manual analysis of images presents challenges for consistency, documentation, and reproducibility. Here we share a combination of complementary computational tools that can be used to partially automate the quantitative analysis of meiotic images. (1) The segmentation of axial and focal staining patterns to automatically measure chromosome axis length and count axis-associated (and non-axis associated) recombination foci; (2) Quantification of focus position along chromosome axes to investigate spatial regulation; (3) Simulation of random distributions of foci within the nucleus or along the chromosome axes to statistically investigate observed foci-axis associations and foci-foci associations; (4) Quantification of chromosome axis proximity to investigate relationships with chromosome synapsis/asynapsis; (5) Quantification of and orientation of focus-axis distances. Together, these tools provide a framework to perform routine documentation and analysis of meiotic images, as well as opening up routes to build on this initial output and perform more detailed analyses.
摘要:
前期I是减数分裂的显着阶段,在此期间,同源染色体配对在一起,并通过减数分裂重组交换DNA。减数分裂染色体传播的荧光显微镜是研究这一过程的核心工具,染色体轴蛋白被可视化为延伸的细丝,重组蛋白在其上定位在焦点模式中。染色体配对和重组是动态过程,一些减数分裂核中可能存在数百个重组灶。由于减数分裂细胞核可以在细胞核内和细胞核之间表现出明显的染色模式变化,特别是在突变体中,图像的手动分析对一致性提出了挑战,文档,和再现性。在这里,我们分享了互补计算工具的组合,可用于部分自动化减数分裂图像的定量分析。(1)轴向和局灶性染色模式的分割,以自动测量染色体轴长度和计数轴相关(和非轴相关)的重组灶;(2)沿染色体轴的焦点位置的定量,以研究空间调控;(3)模拟核内或沿染色体轴的焦点随机分布,以统计方式调查观察到的焦点轴关联和焦点-焦点关联;(4)染色体轴接近度的定量,以研究与突触的关系。一起,这些工具提供了一个框架来执行减数分裂图像的常规文档和分析,以及开辟路线,以建立在这一初始产出的基础上,并进行更详细的分析。