TENT5 cytoplasmic non-canonical poly(A) polymerases regulate the innate immune response in animals. TENT5 cytoplasmic non-canonical poly(A) polymerases regulate the innate immune response in animals

Innate immunity, the first line of host defense against pathogens, is tightly regulated both transcriptionally and post-transcriptionally. Through global transcriptome and proteome analyses in Caenorhabditis elegans, we uncover a modulation of the expression of secreted innate immunity effector proteins by TENT5, one of a recently described family of cytoplasmic poly(A) polymerases. Direct RNA sequencing revealed that TENT-5 polyadenylates mRNAs with signal peptide-encoding sequences, that are translated at the endoplasmic reticulum. Loss of tent-5 function makes worms more susceptible to bacterial infection. Importantly, we demonstrate that the function of TENT-5 in innate immunity is evolutionarily conserved, as its orthologs, TENT5A and TENT5C are induced during macrophage activation and polyadenylate mRNAs, some of which are of genes orthologous to C. elegans TENT-5 targets. In summary, our study reveals cytoplasmic polyadenylation to be a previously unknown component of the post-transcriptional regulation of innate immunity in animals. Overall design: Global transcriptomic analysis of L4-stage tent-5-deficient (TENT-5) and wild-type (WT) worms grown on non-pathogenic Escherichia coli strain HB101 (HB) or infected with Staphylococcus aureus NCTC 8325 (SA) for 8 hours. Other tent-5 IDs: F55A12.9, pqn-44. Transcriptomic analysis of bone marrow-derived macrophages (BMDM) treated with LPS for 8h compared to untreated samples.

先天免疫作为宿主对抗病原体的第一道防线，其转录与转录后调控过程均受到严格管控。本研究通过对秀丽隐杆线虫（Caenorhabditis elegans）开展全局转录组与蛋白质组分析，发现TENT5——新近被鉴定的细胞质多聚腺苷酸聚合酶家族成员之一——可调控分泌型先天免疫效应蛋白的表达水平。直接RNA测序结果显示，TENT-5能够对携带信号肽编码序列的mRNA进行多聚腺苷酸化修饰，这类mRNA会在内质网中完成翻译过程。tent-5功能缺失会导致线虫对细菌感染的易感性显著升高。尤为关键的是，本研究证实TENT5在先天免疫中的功能具有进化保守性：其同源基因TENT5A与TENT5C在巨噬细胞激活过程中会被诱导表达，且同样能够对mRNA进行多聚腺苷酸化修饰，其中部分靶mRNA所对应的基因与秀丽隐杆线虫TENT-5的靶基因同源。综上，本研究揭示了细胞质多聚腺苷酸化是动物先天免疫转录后调控中此前未被探明的关键组成部分。
实验整体设计：对在非致病性大肠杆菌（Escherichia coli）HB101菌株（HB）上培养，或经金黄色葡萄球菌（Staphylococcus aureus）NCTC 8325（SA）感染8小时的L4期tent-5缺陷型（TENT-5）与野生型（WT）线虫进行全局转录组分析。tent-5的其他基因编号为：F55A12.9、pqn-44。对经脂多糖（lipopolysaccharide, LPS）处理8小时的骨髓来源巨噬细胞（bone marrow-derived macrophages, BMDM）与未处理对照组样本进行转录组分析。