Identification of human gene expression induced by 4MU-xyloside treatment. Identification of human gene expression induced by 4MU-xyloside treatment

The Golgi stress response is a homeostatic mechanism that augments the functional capacity of the Golgi apparatus when Golgi function becomes insufficient (Golgi stress). Three response pathways of the Golgi stress response have been identified in mammalian cells, the TFE3, HSP47 and CREB3 pathways, which augment the capacity of specific Golgi functions such as N-glycosylation, anti-apoptotic activity and pro-apoptotic activity, respectively. On the contrary, glycosylation of proteoglycans (PGs) is another important function of the Golgi, although the response pathway upregulating expression of glycosylation enzymes for PGs in response to Golgi stress remains unknown. Here, we found that expression of glycosylation enzymes for PGs was induced upon insufficiency of PG glycosylation capacity in the Golgi (PG-Golgi stress), and that transcriptional induction of genes encoding glycosylation enzymes for PGs was independent of the known Golgi stress response pathways and ER stress response. Promoter analyses of genes encoding these glycosylation enzymes revealed the novel enhancer element PGSE, which regulates their transcriptional induction upon PG-Golgi stress. From these observations, the response pathway we discovered is a novel Golgi stress response pathway, which we have named the PG pathway. Overall design: Three control samples (DMSO-treated) and three 4MU-xyloside-treated samples

高尔基体应激反应（Golgi stress response）是一种稳态调控机制，当高尔基体功能不足（即高尔基体应激，Golgi stress）时，该机制可增强高尔基体的功能储备。目前已在哺乳动物细胞中鉴定出高尔基体应激反应的三条信号通路，分别为TFE3、HSP47与CREB3通路，它们可分别增强N-糖基化、抗凋亡活性以及促凋亡活性这三类特定的高尔基体功能。而与此不同的是，蛋白聚糖（proteoglycans, PGs）糖基化是高尔基体的另一项核心功能，但目前尚未明确响应高尔基体应激、上调蛋白聚糖糖基化酶表达的信号通路。本研究发现，当高尔基体的蛋白聚糖糖基化功能不足（即PG-高尔基体应激，PG-Golgi stress）时，蛋白聚糖糖基化酶的表达会被诱导；且编码这类酶的基因的转录诱导，并不依赖于已知的高尔基体应激反应通路与内质网应激反应（ER stress response）。对上述糖基化酶编码基因的启动子分析显示，存在一种新型增强子元件PGSE，其可调控PG-高尔基体应激状态下这些基因的转录诱导。基于上述实验结果，本研究发现的这条信号通路属于新型高尔基体应激反应通路，我们将其命名为PG通路。实验设计：设置3组对照样本（经二甲基亚砜（dimethyl sulfoxide, DMSO）处理）与3组经4MU-木糖苷处理的样本。