Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno CZ-61265, Czech Republic.
Mendel Centre for Plant Genomics and Proteomics, CEITEC Masaryk University, Brno CZ-62500, Czech Republic.
Nucleic Acids Res. 2023 Jan 11;51(1):420-433. doi: 10.1093/nar/gkac1202.
In contrast to the catalytic subunit of telomerase, its RNA subunit (TR) is highly divergent in size, sequence and biogenesis pathways across eukaryotes. Current views on TR evolution assume a common origin of TRs transcribed with RNA polymerase II in Opisthokonta (the supergroup including Animalia and Fungi) and Trypanosomida on one hand, and TRs transcribed with RNA polymerase III under the control of type 3 promoter, found in TSAR and Archaeplastida supergroups (including e.g. ciliates and Viridiplantae taxa, respectively). Here, we focus on unknown TRs in one of the largest Animalia order - Hymenoptera (Arthropoda) with more than 300 available representative genomes. Using a combination of bioinformatic and experimental approaches, we identify their TRs. In contrast to the presumed type of TRs (H/ACA box snoRNAs transcribed with RNA Polymerase II) corresponding to their phylogenetic position, we find here short TRs of the snRNA type, likely transcribed with RNA polymerase III under the control of the type 3 promoter. The newly described insect TRs thus question the hitherto assumed monophyletic origin of TRs across Animalia and point to an evolutionary switch in TR type and biogenesis that was associated with the divergence of Arthropods.
与端粒酶的催化亚基相反，其 RNA 亚基（TR）在真核生物中在大小、序列和生物发生途径方面高度多样化。目前关于 TR 进化的观点假设，TR 起源于后生动物（包括动物界和真菌界）和锥虫门中由 RNA 聚合酶 II 转录的 TR，另一方面，TR 起源于受类型 3 启动子控制的 RNA 聚合酶 III，在 TSAR 和古植物超群（分别包括纤毛类动物和绿藻门分类群）中发现。在这里，我们专注于最大的动物界订单之一 - 膜翅目（节肢动物）中的未知 TR，该订单有 300 多个可用的代表性基因组。我们使用生物信息学和实验方法的组合来鉴定它们的 TR。与假定的 TR 类型（与它们的系统发育位置相对应的 H/ACA 盒 snoRNAs 由 RNA 聚合酶 II 转录）相反，我们在这里发现了短的 snRNA 类型的 TR，可能由类型 3 启动子控制的 RNA 聚合酶 III 转录。新描述的昆虫 TR 因此质疑了迄今为止在动物界中普遍存在的 TR 单系起源，并指出了与节肢动物分化相关的 TR 类型和生物发生的进化转变。
