美国洛克菲勒大学William M. Schneider等研究人员合作发现，乙型肝炎病毒深度突变筛选揭示顺式偏好逆转录机制。该研究于2024年5月8日在线发表于国际一流学术期刊《细胞》。

研究人员将基于RNA的乙型肝炎病毒（HBV）细胞培养系统与深度突变筛选（DMS）相结合，以解除HBV基因组中顺式和反式作用序列要求的耦合。研究结果支持聚合酶翻译的泄露核糖体扫描模式，提供了单核苷酸分辨率的HBV聚合酶适配性图谱，并确定了与HBV聚合酶终止密码子相邻的、使核糖体停滞的保守突变。进一步的实验表明，停滞的核糖体将新生聚合酶拴在其模板RNA上，确保顺式偏好RNA包装和HBV基因组的反转录。

据悉，HBV是一种小型双链DNA病毒，长期感染2.96亿人。其紧凑的基因组中有一半以上在两个重叠的阅读框中编码蛋白质，在演化过程中，多种选择压力可能作用于共享核苷酸。

附：英文原文

Title: Deep mutational scanning of hepatitis B virus reveals a mechanism for cis-preferential reverse transcription

Author: Yingpu Yu, Maximilian A. Kass, Mengyin Zhang, Noor Youssef, Catherine A. Freije, Kelly P. Brock, Lauren C. Aguado, Leon L. Seifert, Sanjana Venkittu, Xupeng Hong, Amir Shlomai, Ype P. de Jong, Debora S. Marks, Charles M. Rice, William M. Schneider

Issue&Volume: 2024-05-08

Abstract: Hepatitis B virus (HBV) is a small double-stranded DNA virus that chronically infects296 million people. Over half of its compact genome encodes proteins in two overlappingreading frames, and during evolution, multiple selective pressures can act on sharednucleotides. This study combines an RNA-based HBV cell culture system with deep mutationalscanning (DMS) to uncouple cis- and trans-acting sequence requirements in the HBV genome. The results support a leaky ribosomescanning model for polymerase translation, provide a fitness map of the HBV polymeraseat single-nucleotide resolution, and identify conserved prolines adjacent to the HBVpolymerase termination codon that stall ribosomes. Further experiments indicated thatstalled ribosomes tether the nascent polymerase to its template RNA, ensuring cis-preferential RNA packaging and reverse transcription of the HBV genome.

DOI: 10.1016/j.cell.2024.04.008

Source: https://www.cell.com/cell/abstract/S0092-8674(24)00403-3