在一个非细分负链RNA病毒的大型蛋白质内,共同转录的mRNA成熟的完整途径
Minako Ogino1, Todd J Green2, Tomoaki Ogino1
1Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43614, USA.
Nucleic acids research
|July 30, 2024
概括
非细分的负链RNA病毒使用单个大蛋白 (L) 共同转录地封锁和多基化mRNAs. 这种全合一的病毒mRNA组装机器确保了正确的病毒基因表达.
科学领域:
- 病毒学 病毒学
- 分子生物学分子生物学
- 在RNA生物学,RNA生物学.
背景情况:
- 非细分负链 (NNS) RNA 病毒,包括狂犬病,尼帕病毒和埃博拉病毒,合成5'-封顶和3'-多基化mRNA.
- 这些病毒mRNA模仿了较高的真核mRNA的结构,表明了保存的调节机制.
研究的目的:
- 开发一种转录延长合的mRNA前封闭系统,用于囊性口腔炎病毒 (VSV),一种代表性的NNSRNA病毒.
- 阐明VSV大蛋白 (L) 对共转录前mRNA修改的序列步骤和要求.
主要方法:
- 开发一种新型的转录系统,以研究VSVRNA合成期间的mRNA前封闭.
- 对VSV L蛋白的酶活性进行生物化学分析,包括其依赖RNA的RNA聚合酶 (RdRp),GDP聚核酸转移酶 (PRNTase) 和甲基转移酶 (MTase) 域.
- 在延长过程中对帽子甲基化的长度依赖要求的调查.
主要成果:
- 在VSV L蛋白质催化所有前mRNA修饰共同转录:5'-封闭,2'-O-甲基化,瓜-N7-甲基化 (封闭1),和3'-多基化.
- PRNTase域通过共价中间体产生至少18个核酸的封闭式前mRNA.
- 序列盖甲基化只发生在延长复合体内的40个核酸或更长的前mRNA中.
结论:
- 该VSV L蛋白质作为单个多,具有病毒mRNA合成和修改所需的所有酶活性.
- 在延长复合体内形成前mRNA闭环结构对于1帽形成至关重要.
- NNSRNA病毒L蛋白作为集成的mRNA组装机械,对于病毒复制和病原发生是必不可少的.
相关概念视频
01:10Retrovirus Life Cycles
45.8K
Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the...
45.8K
02:22Regulated mRNA Transport
6.3K
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing...
6.3K
02:27Nonsense-mediated mRNA Decay
2.8K
2.8K
02:28Leaky Scanning
5.1K
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R...
5.1K
02:01pre-mRNA Processing
52.8K
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl...
52.8K
02:31Nuclear Export of mRNA
7.6K
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
7.6K