ポリアデニル化因子CPSF-73は,プリ-mRNA 3'-end-processing endonucleaseである
Corey R Mandel1, Syuzo Kaneko, Hailong Zhang
1Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
Nature
|November 28, 2006
まとめ
分裂およびポリアデニレーション特異性因子73 (CPSF-73) タンパク質は,メッセンジャーRNA前駆体 (pre-mRNAs) の処理を担当するエンドヌクレアゼとして特定されています. この発見は,CPSF-73の直接的な証拠を提供します.
科学分野:
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
背景:
- ユカリオットのプレ-mRNA処理には,3'-end cleavageとポリアデニレーションが含まれています.
- この重要なステップに起因する特定のエンドヌクレアース酵素は,未だに特定されていない.
- 以前の研究では,CPSF-73が潜在的な候補であると示唆されたが,直接的な実験的な確認は得られなかった.
研究 の 目的:
- 人間のCPSF-73と酵母CPSF-100.0の結晶構造を決定する.
- CPSF-73.3の酵素活性と基板特異性を調査する.
- プレ-mRNA処理におけるCPSF-73の役割に関する直接的な実験的証拠を提供すること.
主な方法:
- X線結晶学を用いて,ヒトのCPSF-73と酵母CPSF-100の構造を決定した.
- インビトロ酵素測定のための再結合CPSF-73の浄化.
- サイト・ディレクテッド・ミュータゲネシス (SITE-DIRECTED MUTAGENESIS) は,活性サイトにおける亜鉛イオンの機能を調べるためのものです.
主要な成果:
- 結晶構造は,CPSF-73とCPSF-100がメタロベータラクタマースとベータ-CASPドメインを持っていることを明らかにしました.
- 2つの亜鉛イオンを含むCPSF-73の活性サイトは,これらのドメインのインターフェイスに位置しています.
- 浄化されたCPSF-73はRNAエンドヌクレアース活性を示し,これは亜鉛結合に影響する変異によって廃止された.
結論:
- CPSF-73は,pre-mRNA 3'-end処理を担当するエンドヌクレアースとして直接確認されています.
- 構造的および生化学的なデータは,RNA成熟におけるCPSF-73のメカニズムを明らかにします.
- この発見は,真核生物の遺伝子発現における根本的なステップを明らかにしている.
関連する概念動画
01:32RNA Splicing
Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...
02:01pre-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...
02:01Pre-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...
01:32RNA Splicing
Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...
02:27Nonsense-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,...
01:35Pre-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...