BioSciences Institute, University College Cork, Cork, Ireland.
Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
Virology. 2010 Mar 30;399(1):153-166. doi: 10.1016/j.virol.2009.12.033. Epub 2010 Jan 25.
Flaviviruses have a positive-sense, single-stranded RNA genome of approximately 11 kb, encoding a large polyprotein that is cleaved to produce approximately 10 mature proteins. Cell fusing agent virus, Kamiti River virus, Culex flavivirus and several recently discovered flaviviruses have no known vertebrate host and apparently infect only insects. We present compelling bioinformatic evidence for a 253-295 codon overlapping gene (designated fifo) conserved throughout these insect-specific flaviviruses and immunofluorescent detection of its product. Fifo overlaps the NS2A/NS2B coding sequence in the -1/+2 reading frame and is most likely expressed as a trans-frame fusion protein via ribosomal frameshifting at a conserved GGAUUUY slippery heptanucleotide with 3'-adjacent RNA secondary structure (which stimulates efficient frameshifting in vitro). The discovery bears striking parallels to the recently discovered ribosomal frameshifting site in the NS2A coding sequence of the Japanese encephalitis serogroup of flaviviruses and suggests that programmed ribosomal frameshifting may be more widespread in flaviviruses than currently realized.
黄病毒具有约 11kb 的正链单链 RNA 基因组，编码一个大型多蛋白，该多蛋白被切割后产生大约 10 个成熟蛋白。细胞融合剂病毒、卡米提河病毒、库蚊黄病毒和最近发现的几种黄病毒没有已知的脊椎动物宿主，显然只感染昆虫。我们提出了令人信服的生物信息学证据，证明在这些昆虫特异性黄病毒中存在一个 253-295 密码子重叠基因（命名为 fifo），并通过免疫荧光检测到其产物。Fifo 在 -1/+2 阅读框中与 NS2A/NS2B 编码序列重叠，最有可能通过核糖体移码以保守的 GGAUUUY 滑动七核苷酸和 3'-相邻 RNA 二级结构（在体外刺激有效移码）表达为跨框架融合蛋白。这一发现与最近在日本脑炎血清群黄病毒的 NS2A 编码序列中发现的核糖体移码位点惊人地相似，表明程序性核糖体移码可能比目前认识到的更为广泛地存在于黄病毒中。
