Department of Cytophysiology, University of Łódź, Poland.
Eur J Histochem. 2012 May 30;56(2):e13. doi: 10.4081/ejh.2012.13.
In this study, using the immunofluorescent method, the immunopositive signals to ubiquitin and proteasomes in nucleoli of root meristematic cells of soybean seedlings have been observed. In fact, those signals were present exclusively in nucleolar vacuoles. No signals were observed in the nucleolar territory out of the nucleolar vacuoles or in the nucleoli without vacuoles. The ubiquitin-proteasome system (UPS) may act within the nucleoli of plants with high metabolic activities and may provide an additional level of regulation of intracellular proteolysis via compartment-specific activities of their components. It is suggested that the presence of the UPS solely in vacuolated nucleoli serves as a mechanism that enhances the speed of ribosome subunit production in very actively transcribing nucleoli. On the other hand, nucleolar vacuoles in a cell/nucleus could play additional roles associated with temporary sequestration or storage of some cellular factors, including components of the ubiquitin-proteasome system.
在这项研究中，使用免疫荧光法，观察到大豆幼苗根尖分生细胞核仁中泛素和蛋白酶体的免疫阳性信号。事实上，这些信号只存在于核仁液泡中。在核仁液泡之外的核仁区域或没有液泡的核仁中没有观察到信号。泛素-蛋白酶体系统 (UPS) 可能在代谢活性高的植物核仁中发挥作用，并通过其成分的特定于隔室的活性提供细胞内蛋白水解的额外调节水平。有人认为，UPS 仅存在于液泡化核仁中，是一种机制，可以提高非常活跃转录核仁中核糖体亚基产生的速度。另一方面，细胞/核中的核仁液泡可能发挥与某些细胞因子（包括泛素-蛋白酶体系统的成分）的暂时隔离或储存相关的额外作用。
