Alfredsson-Timmins Jenny, Kristell Carolina, Henningson Frida, Lyckman Sara, Bjerling Pernilla
Department of Medical Biochemistry and Microbiology (IMBIM), University of Uppsala, Uppsala, Sweden.
Chromosoma. 2009 Feb;118(1):99-112. doi: 10.1007/s00412-008-0180-6. Epub 2008 Oct 21.
There are several documented events of changes in subnuclear localization during gene activation. However, there are conflicting data on whether the nuclear periphery is a compartment for gene repression or activation and whether genes are moved to the pores at the nuclear membrane (NM) or not during gene activation. Nitrogen starvation of fission yeast serves as a good model system for studying gene induction, as it causes fast regulation of hundreds of genes. In this study, the subnuclear localization of two gene clusters repressed by nitrogen was investigated. During normal growth conditions, the gene clusters localized to the nuclear periphery at the opposite side of the nucleus as compared to the spindle pole body. This constrained localization was dependent on the histone deacetylase Clr3, known to transcriptionally repress genes in these clusters. Already 20 min after nitrogen depletion, drastic changes in subnuclear localization of the two loci were observed, away from the NM toward the nuclear interior. At least for one of the clusters, the movement was clearly transcription dependent. Data presented in this paper illustrates how interconnected events of gene activation and nuclear reorganization are as well as provides a suggestion of how nuclear organization might be maintained.
有几起关于基因激活过程中亚核定位变化的记录事件。然而，关于核周边是基因抑制还是激活的区域，以及基因在激活过程中是否会移动到核膜（NM）的孔处，存在相互矛盾的数据。裂殖酵母的氮饥饿是研究基因诱导的良好模型系统，因为它会导致数百个基因的快速调控。在本研究中，对两个受氮抑制的基因簇的亚核定位进行了研究。在正常生长条件下，与纺锤极体相比，基因簇定位于细胞核相对一侧的核周边。这种受限的定位依赖于组蛋白脱乙酰酶Clr3，已知其在转录水平上抑制这些簇中的基因。氮耗尽后仅20分钟，就观察到两个基因座的亚核定位发生了剧烈变化，从远离核膜向核内部移动。至少对于其中一个簇，这种移动明显依赖于转录。本文提供的数据说明了基因激活和核重组的相互关联事件，以及对核组织如何维持提供了一个建议。
