概括
菌体T4RNA处理需要特定的酶. 一种突变的大肠杆菌菌株阻止了这一过程,这表明至少有两种3'核糖核酶对于转移RNA成熟至关重要.
科学领域:
- 分子生物学分子生物学
- 病毒学 病毒学
- 生物化学 生物化学
背景情况:
- 菌体T4前体RNA经受酶性处理,形成功能性林和氨酸转移RNA.
- 这种成熟过程包括从RNA链的3'端去除核酸.
- 之前的研究发现了一种干扰T4血清转移RNA抑制器功能的大肠杆菌突变.
研究的目的:
- 为了研究一种特定的Escherichia coli突变体在细菌T4转移RNA生物合成中的作用.
- 为了确定参与前体RNA成熟的酶性活动.
- 确定多个核糖核酶是否负责3'终端处理.
主要方法:
- 感染特定的埃舍里希亚大肠杆菌突变体与菌体T4.
- 在感染突变细胞中对前体RNA成熟的分析.
- 检测无细胞提取物对3'核糖核酶活性的检测.
主要成果:
- 在突变的大肠杆菌菌株中,T4林和血清前体RNA的成熟被阻止.
- 突变的无细胞提取物缺乏一种酶活性,这种酶能从特定的RNA链中去除3'核酸.
- 其他T4转移RNA的成熟受到了不同的影响,其中一些被阻断,而另一些则尽管去除了3'核酸,但仍正常进行.
结论:
- 研究的埃舍里希亚大肠杆菌突变破坏了细菌体T4转移RNA生物合成.
- 结果表明,至少有两种不同的3'核糖核酶参与了菌体T4转移RNA的成熟.
- 在突变中受影响的特定核糖核酶及其与其他核糖核酶的关系仍然需要阐明.
相关概念视频
Mismatch Repair
Overview
Nuclear Export of mRNA
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...
Transfer RNA Synthesis
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Nonsense-mediated mRNA Decay
The Upf proteins that carry out nonsense-mediated decay (NMD) are found in all eukaryotic organisms, including humans. Each protein has an individual role, but they need to work in collaboration. Upf1 is an ATP-dependent RNA helicase that unwinds the RNA helix. Because Upf1 can unwind any RNA, Upf2 and Upf3 are required to help Upf1 discriminate between nonsense and normal mRNAs.
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Nonsense-mediated mRNA Decay
The Upf proteins that carry out nonsense-mediated decay (NMD) are found in all eukaryotic organisms, including humans. Each protein has an individual role, but they need to work in collaboration. Upf1 is an ATP-dependent RNA helicase that unwinds the RNA helix. Because Upf1 can unwind any RNA, Upf2 and Upf3 are required to help Upf1 discriminate between nonsense and normal mRNAs.
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Mismatch Repair
Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...


