Chu Catherine G, Lang Nick, Walsh Erin, Zheng Mindy D, Manning Gianna, Shalin Kiruba, Cunha Lyssa M, Faucon Kate E, Kam Nicholas, Folan Sara N, Desai Arav P, Naughton Emily, Abreu Jaylynn, Carson Alexis M, Wald Zachary L, Khvorova-Wolfson Dasha, Phan Leena, Lee Hannah, Pho Mai, Prince Kelsey, Dorfman Katherine, Bahiru Michael Seifu, Stephens Andrew D
Biology department, University of Massachusetts Amherst, Amherst, MA 01003, USA.
Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA.
bioRxiv. 2025 Feb 25:2025.02.24.639904. doi: 10.1101/2025.02.24.639904.
The nucleus houses genetic information and functions separate from the rest of the cell. Loss of nuclear shape results in nuclear ruptures. Nuclear blebs are deformations identified by decreased DNA density, while lamin B levels vary drastically. To determine if decreased lamin B levels are due to nuclear rupture, we used immunofluorescence to measure levels of lamin B and emerin, a nuclear envelope protein that enriches to sites of nuclear rupture. We observed that cell types that exhibit decreased levels of lamin B also show an enrichment of emerin in nuclear blebs. Oppositely, in other cell types, nuclear blebs display maintained levels of lamin B1 and showed no emerin enrichment. To determine how nuclear rupture affects DNA damage, we time lapse imaged nuclear rupture dynamics then fixed the same cells to conduct immunofluorescence of γH2AX and emerin. We find that DNA damage levels are higher in blebbed nuclei independent of nuclear rupture. Thus, we confirm that lamin B1 loss in nuclear blebs is due to nuclear rupture and blebbed nuclei have increased DNA damage that is independent of rupture.
细胞核容纳遗传信息，其功能与细胞的其他部分相分离。核形状的丧失会导致核破裂。核泡是由DNA密度降低所识别的变形，而核纤层蛋白B的水平则有很大变化。为了确定核纤层蛋白B水平降低是否是由于核破裂所致，我们使用免疫荧光法来测量核纤层蛋白B和Emerin（一种富集于核破裂部位的核膜蛋白）的水平。我们观察到，核纤层蛋白B水平降低的细胞类型在核泡中也显示出Emerin的富集。相反，在其他细胞类型中，核泡显示核纤层蛋白B1水平保持不变，且未显示Emerin富集。为了确定核破裂如何影响DNA损伤，我们通过延时成像观察核破裂动态，然后固定相同的细胞以进行γH2AX和Emerin的免疫荧光检测。我们发现，有核泡的细胞核中的DNA损伤水平更高，且与核破裂无关。因此，我们证实核泡中核纤层蛋白B1的丧失是由于核破裂所致，并且有核泡的细胞核具有增加的DNA损伤，且这种损伤与破裂无关。
