Chapter 12 Transcription Activators in Eukaryotes CopyrightThe McGraw-Hill Companies,Inc.Permission required for reproduction or display. Courtesy Nicola P.Pavletich,Sloan-Kettering Cancer Center,Science(15 July 1994)cover.Copyright AAAS
Chapter 12 Transcription Activators in Eukaryotes
12.1 Categories of Activators(激活因子) Activators (gene-specific TF)can stimulate or inhibit transcription by RNA polymerase ll Structure is composed of at least 2 functional domains(功能域) - DNA-binding domain(DNA结合域) -Transcription-activation domain(转录激活域) - Many also have a dimerization domain(二聚 作用域) 12-2
12-2 12.1 Categories of Activators (激活因子) ✓ Activators (gene-specific TF) can stimulate or inhibit transcription by RNA polymerase II ✓ Structure is composed of at least 2 functional domains (功能域) – DNA-binding domain (DNA结合域) – Transcription-activation domain (转录激活域) – Many also have a dimerization domain (二聚 作用域)
DNA-Binding Domains √Protein domain(蛋白质结构域)isan independently folded region of a protein DNA-binding domains have DNA-binding motif (DNA结合基序) -Part of the domain having characteristic shape specialized for specific DNA binding -Most DNA-binding motifs fall into 3 classes 1.Zinc-Containing Modules(含锌组件) 2.Homeodomains(同源域) 3.bZIP and bHLH Motifs(Bzip和bHLH基序) 12-3
12-3 DNA-Binding Domains ✓ Protein domain (蛋白质结构域) is an independently folded region of a protein ✓ DNA-binding domains have DNA-binding motif (DNA结合基序) – Part of the domain having characteristic shape specialized for specific DNA binding – Most DNA-binding motifs fall into 3 classes 1. Zinc-Containing Modules (含锌组件) 2. Homeodomains (同源域) 3. bZIP and bHLH Motifs (Bzip和bHLH基序)
Zinc-Containing Modules There are at least 3 kinds of zinc-containing modules that act as DNA-binding motifs All use one or more zinc ions to create a shape to fit an a-helix of the motif into the DNA major groove -Zinc fingers(锌指)：TFlA,Sp1 -Zinc modules(锌组件)：nuclear receptor -Modules containing 2 zinc and 6 cysteines (含两个锌离子和六个半胱氨酸组件)：GAL4 12-4
12-4 Zinc-Containing Modules ✓ There are at least 3 kinds of zinc-containing modules that act as DNA-binding motifs ✓ All use one or more zinc ions to create a shape to fit an a-helix of the motif into the DNA major groove – Zinc fingers (锌指): TFII A,Sp1 – Zinc modules (锌组件):nuclear receptor – Modules containing 2 zinc and 6 cysteines (含两个锌离子和六个半胱氨酸组件):GAL4
Homeodomains These domains contain about 60 amino acids Resemble the helix-turn-helix proteins in structure and function Found in a variety of activators Originally identified in homeobox proteins (同源盒蛋白)regulating fruit fly development 12-5
12-5 Homeodomains ✓These domains contain about 60 amino acids ✓Resemble the helix-turn-helix proteins in structure and function ✓Found in a variety of activators ✓Originally identified in homeobox proteins (同源盒蛋白) regulating fruit fly development