美国斯坦福大学Andrew Z. Fire等研究人员合作发现人类微生物组的类病毒定殖者。该项研究成果发表在2024年10月30日出版的《细胞》上。

研究人员描述了“方尖碑”，这是一类具有遗传特性的RNA元素，分享几个特性：（1）表面上呈环状的约1 kb基因组组装；（2）预测的杆状全基因组二级结构；（3）编码一种新型“Oblin”蛋白超家族的开放阅读框。方尖碑的一个子集包括一种变异的自切割锤头核酶。方尖碑形成了自己的系统发育群，与已知生物因子没有可检测的相似性。

通过全球调查，研究人员从不同生态位识别出29959个不同的方尖碑（在90%序列相似度下聚类）。方尖碑在人体微生物组中普遍存在，在大约7%（29/440）和约50%（17/32）的查询粪便和口腔转录组中被检测到。研究人员确定了链球菌（Streptococcus sanguinis）作为特定方尖碑的细胞宿主，并发现该方尖碑的维持对细菌生长并不是必需的。

这些观察表明，方尖碑是一类尚未确定影响的多样化RNA，已经在人体和全球微生物组中定殖且并未被注意到。

附：英文原文

Title: Viroid-like colonists of human microbiomes

Author: Ivan N. Zheludev, Robert C. Edgar, Maria Jose Lopez-Galiano, Marcos de la Pea, Artem Babaian, Ami S. Bhatt, Andrew Z. Fire

Issue&Volume: 2024-10-30

Abstract: Here, we describe “obelisks,” a class of heritable RNA elements sharing several properties: (1) apparently circular RNA ～1 kb genome assemblies, (2) predicted rod-like genome-wide secondary structures, and (3) open reading frames encoding a novel “Oblin” protein superfamily. A subset of obelisks includes a variant hammerhead self-cleaving ribozyme. Obelisks form their own phylogenetic group without detectable similarity to known biological agents. Surveying globally, we identified 29,959 distinct obelisks (clustered at 90% sequence identity) from diverse ecological niches. Obelisks are prevalent in human microbiomes, with detection in ～7% (29/440) and ～50% (17/32) of queried stool and oral metatranscriptomes, respectively. We establish Streptococcus sanguinis as a cellular host of a specific obelisk and find that this obelisk’s maintenance is not essential for bacterial growth. Our observations identify obelisks as a class of diverse RNAs of yet-to-be-determined impact that have colonized and gone unnoticed in human and global microbiomes.

DOI: 10.1016/j.cell.2024.09.033

Source: https://www.cell.com/cell/abstract/S0092-8674(24)01091-2