中国水产科学2018，Vol.25Issue(3)：494-502,9.DOI:10.3724/SP.J.1118.2018.17258
高温胁迫下刺参肠道细胞应激颗粒标记蛋白TIA-1的表达特征
Expression character analysis of the stress granule marker TIA-1 in the intestinal cells of sea cucumber in response to heat stress
摘要
Abstract
In response to environmental stresses, such as heat shock, oxidative stress, and viral infection, arrest of translation initiation reduces energy-expensive cellular processes and conserves the energy required for the repair of cellular damage. Untranslated mRNAs that accumulate in these cells move to discrete cytoplasmic foci known as stress granules (SGs). SGs are characterized by the presence of translational initiation factors such as eIF4E, eIF4G, eIF4A, eIF4B, eIF3, eIF2, poly(A)-binding protein, and stalled 40S ribosomal units. The best-known pro-teins integral to SG formation are T-cell intracellular antigen (TIA) proteins, which are considered robust markers of SGs. The assembly of SGs, one of the most important post-transcriptional mechanisms, helps cells to survive under adverse environmental conditions. Currently, there is no information on the cell-protective roles of SGs in marine invertebrates under environmental stress. In the present study, we hypothesized that TIA-1, an mRNA-binding protein that can aggregate within granules, may play a significant role in the sea cucumber Apos-tichopus japonicus in response to heat stress. We characterized the amino sequence of A. japonicus TIA-1. The full-length cDNA of TIA-1 is 3108 bp, comprising a 5′-untranslated region (UTR) of 16 bp, 3′-UTR of 1808 bp, and open reading frame (ORF) of 1284 bp. The ORF encodes 427 amino acids, with a calculated molecular mass of 48.07 kD and 6.19 theoretical isoelectric point. Structural analysis showed that A. japonicus TIA-1 has three N-terminal RNA-recognition motifs and two C-terminal low-complexity regions, which are related to prion pro-teins and have the capacity to form reversible aggregates. Phylogenetic analyses revealed that A. japonicus TIA-1 is closely related to Lingula anatina TIAR. Moreover, we detected whole-cell and subcellular protein expression levels of TIA-1 by using western blotting. The localization of TIA-1 to subnuclear structures was assessed using immunofluorescence analysis. The results showed that the expression level of TIA-1 in cytoplasmic fractions un-der heat stress (25℃) was significantly increased when compared with the control group (15℃). The fluorescence signals of TIA-1 were observed to be translocated from the nucleus to the cytoplasm in response to heat stress, which suggests that TIA-1 may be involved in the formation of SGs to protect the stressed intestinal cells of A. japonicus under high temperature conditions. We identified a potential novel cytoprotective mechanism in re-sponse to heat stress in A. japonicus from the viewpoint of post-transcriptional regulation, which may play an im-portant role in reducing the translational rates and/or mRNA processing under unfavorable environmental condi-tions in marine invertebrates.关键词
刺参/肠道细胞/TIA-1/应激颗粒/高温胁迫Key words
Apostichopus japonicus/sea cucumber intestinal cell/TIA-1/stress granule/heat stress分类
农业科技引用本文复制引用
王莎莎,王天明,秦英惠,陈慕雁..高温胁迫下刺参肠道细胞应激颗粒标记蛋白TIA-1的表达特征[J].中国水产科学,2018,25(3):494-502,9.基金项目
国家自然科学基金项目(31472257). （31472257）
