活性化欠陥のTBP変異が酵母における転写開始に及ぼす影響
T K Kim1, S Hashimoto, R J Kelleher
1Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10021.
Nature
|May 19, 1994
まとめ
研究者らは,基礎活性に影響を与えることなく,活性化剤依存転写をブロックする酵母TATA結合ポリペプチド (TBP) 変異を特定しました. これは,GAL4-VP16のようなアクティベーターが,TBPとTFIIBと相互作用して,転写開始を調節する方法を示しています.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝子規制 遺伝子規制
- バイオケミストリー バイオケミストリー
背景:
- RNAポリメラーゼIIによる転写開始には,一般的な因子とプロモーター要素が含まれます.
- アクティベーターはトランスクリプションを調節し,TFIIDやTFIIBのような一般的なトランスクリプション因子をターゲットにすることが多い.
- アクティベーターの機能を理解するには,トランスクリプション機構との相互作用の詳細な知識が必要です.
研究 の 目的:
- 転写開始におけるアクティベーター機能の分子メカニズムを調査する.
- アクティバーター,TBP,TFIIBとの間の特定の相互作用を特定する.
- アクティベータ依存転写がどのように選択的に調節されるかを解明する.
主な方法:
- 酵母TBPのサイト指向型変異は,特定の変異を生成します.
- TBP変異がベースおよびアクティベータ依存転写に与える影響を評価する.
- アクティベーターとTBPミュータントの存在下で,TFIIBのプレイニシテーション複合体への勧誘を調査する.
主要な成果:
- 特定された酵母TBP変異は,GAL4-VP16依存転写を選択的に損なうが,基礎転写を損なうものではない.
- GAL4-VP16が,TFIIBの早期のプレイニシアチブ・コンプレックスへの採用に影響することを実証した.
- VP16またはTFIIBとの相互作用に影響するTBP変異が,この採用プロセスを破壊することを示した.
結論:
- GAL4-VP16の機能には,TBPとの直接的な相互作用が含まれています.
- アクティベーター機能は,特定のTBP-TFIIB-プロモーター複合体の誘導または安定化につながる.
- これらの発見は,アクティベーション媒介による転写調節のメカニズムについての洞察を提供します.
関連する概念動画
RNA Polymerase II Accessory Proteins
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
Eukaryotic Transcription Activators
Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
Eukaryotic Transcription Inhibitors
Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Transcription Attenuation in Prokaryotes
Transcriptional attenuation occurs when RNA transcription is prematurely terminated due to the formation of a terminator mRNA hairpin structure. Bacteria use these hairpins to regulate the transcription process and control the synthesis of several amino acids including histidine, lysine, threonine, and phenylalanine. Transcription attenuation takes place in the non-coding regions of mRNA.
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
Transcription Initiation
Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the other hand, transcription in eukaryotes requires additional proteins, called transcription factors, to first bind to the promoter region in the DNA template. This binding helps recruit the specific RNAP that can assemble on the DNA and start transcription.
The promoters and enhancers and their accessory proteins allow tight regulation of...
The promoters and enhancers and their accessory proteins allow tight regulation of...
General Transcription Factors
Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of hemoglobin, is present in all cells of the body. However, it is only expressed in red blood cells because the transcription factors that can bind to the promoter sequences of the beta globin gene are only expressed in these cells. Tissue-specific transcription factors also ensure that mutations in these factors may impair only the function of...


