相关实验视频
Updated: Jun 24, 2026

07:42
Dissection of Hippocampal Dentate Gyrus from Adult Mouse
Published on: November 17, 2009
概括
研究人员确定了子α和β全球蛋白信使RNAs (mRNAs) 的5'终端核酸序列. 这两种序列都具有相同的甲基化帽结构和初始核酸,在序列中以后会出现变异.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 生物化学 生物化学
背景情况:
- 使者RNA (mRNA) 在蛋白质合成中起着至关重要的作用.
- mRNA的5'终端含有调节元素,包括帽子结构.
- 了解mRNA序列对于破译基因表达至关重要.
研究的目的:
- 为了确定子α和β球蛋白mRNA的5'末端的精确核酸序列.
- 为了确定这两个重要的全球蛋白mRNAs的5'序列的相似性和差异.
- 为了研究在5'端附近潜在的启动器子的存在和位置.
主要方法:
- 周期性氧化和3H-博化物标签以识别盖结构 (m7G5'ppp).
- 酶处理 (β消除,基化酶) 来去除帽子.
- 使用T4多核酸酶和-32P-ATP对5'端进行32P标记.
- 在化条件下进行聚烯胺凝电泳,以进行分离.
- RNA测序以确定核酸的顺序.
主要成果:
- 甲基化帽结构 (m7G5'ppp) 在阿尔法和β环球蛋白mRNA的5'终端得到证实.
- 5'终端序列被确定为alpha--m7G5'ppp5m6AmC(m) ACUUCUGG和β--M7G5'ppp5m6AmC(m) ACUUGCUUUUGACACAA. 这两种序列被确定为alpha--m7G5'ppp5m6AmC.
- 两个序列在帽结构后的前六个核酸共享同一性,然后分离.
- 在alpha-globin mRNA的前10个核酸和β-globin mRNA的前19个核酸中没有发现启动符号.
结论:
- 子α和β全球蛋白mRNA具有共同的甲基化帽结构和初始序列元素.
- 序列分歧发生在最初的保存区域之后,这表明不同的调节作用或翻译启动机制.
- 早期发起者编码子的缺失凸显了5'未翻译区域在翻译控制中的重要性.
相关概念视频
pre-mRNA Processing
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 guanosine). This 5’ cap helps the...
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 guanosine). This 5’ cap helps the...
Pre-mRNA Processing
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 guanosine). This 5’ cap helps the...
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 guanosine). This 5’ cap helps the...
Ribosomal RNA Synthesis
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
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...
Leaky Scanning
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 stands for...
Pre-mRNA Processing: Modification of pre-mRNA Ends
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 (7-methyl guanosine). This 5' cap helps the cell...
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 (7-methyl guanosine). This 5' cap helps the cell...

