Elucidating the mechanisms of chromosome length sensing by the synaptonemal complex

在本财政年度，我们通过对体内条件进行一些调整来改进我们的成像技术。我们成功地跟踪了mmaple3标记的SYP-3蛋白在秀丽隐杆线虫减数分裂染色体内和染色体间的动态运动，同时利用egfp标记的COSA-1蛋白可视化了交叉指定位点的位置。虽然COSA-1和未激活的mMaple3-SYP-3在绿色通道中都是荧光的，但我们发现在SYP-3染色的线性信号背景下，标记交叉的COSA-1焦点是明确可见的。因此，我们能够克服只有两个荧光通道来测量三个所需信号（非激活的mMaple3-SYP-3、激活的mMaple3-SYP-3和COSA-1）的限制。此外，我们开发了一套更新的图像分析工具（https://github.com/carltonlab/carltonlab_imagej_tools）和模拟软件（https://github.com/carltonlab/scsim），我们使用它们来生成和测试我们的扩散和积累模型的预测。根据研究计划，领导该项目的研究生在2022财年的减数分裂戈登会议上介绍了我们正在进行的工作，并收到了研究界的宝贵反馈。

In this fiscal year we have improved our imaging techniques by making several adjustments to the in vivo conditions. We have succeeded in following the dynamic movement of mMaple3-labeled SYP-3 protein within and between meiotic chromosomes of C. elegans, while simultaneously visualizing the position of crossover designation sites by using eGFP-labeled COSA-1 protein. While both COSA-1 and non-activated mMaple3-SYP-3 are fluorescent in the green channel, we have found conditions where the COSA-1 foci that mark crossovers are unambiguously visible against the background of the linear signal characterizing SYP-3 staining. Thus, we were able to overcome the limitation of having only two fluorescent channels to measure three desired signals (non-activated mMaple3-SYP-3, activated mMaple3-SYP-3, and COSA-1). Further, we have developed an updated set of image analysis tools (https://github.com/carltonlab/carltonlab_imagej_tools) and simulation software (https://github.com/carltonlab/scsim) that we use to generate and test predictions of our diffusion and accumulation model.The graduate student leading this project has presented our work-in-progress at the Meiosis Gordon Conference in FY2022, in accordance with the research plan, and received valuable feedback from the research community.