Chapter 17 Gene Regulation in Eukaryotes
Chapter 17 Gene Regulation in Eukaryotes
Similarity of regulation between eukaryotes and prokaryote 1. Principles are the same signals activators and repressors, recruitment and allostery, cooperative bind ding Expression of a gene can be regulated at the similar steps, and the initiation of transcription is the most pervasively regulated step
Similarity of regulation between eukaryotes and prokaryote 1. Principles are the same: signals, activators and repressors, recruitment and allostery, cooperative binding 2. Expression of a gene can be regulated at the similar steps, and the initiation of transcription is the most pervasively regulated step
Difference in requlation between eukaryotes and prokaryote 1. Pre-mRNA splicing adds an important step for regulation 2. The eukaryotic transcriptional machinery is more elaborate than its bacterial counterpart 3/ Nucleosomes and /their modifiers influence access to genes 4. Many eukaryotic genes have more regulatory binding sites and are controlled by more requlatory proteins than are bacterial genes
Difference in regulation between eukaryotes and prokaryote 1. Pre-mRNA splicing adds an important step for regulation. 2. The eukaryotic transcriptional machinery is more elaborate than its bacterial counterpart. 3. Nucleosomes and their modifiers influence access to genes. 4. Many eukaryotic genes have more regulatory binding sites and are controlled by more regulatory proteins than are bacterial genes
A lot more regulator bindings sites in multicellular organisms reflects the more extensive signal integration regulatory promoter Bacteria sequence Yeast Human Fg。17-1
A lot more regulator bindings sites in multicellular organisms reflects the more extensive signal integration Fig. 17-1 Bacteria Yeast Human
Enhancer: a given site binds regulator responsible for activating the gene Alternative enhancer binds different groups of regulators and control expression of the same gene at different times and laces in responsible to different signals. Activation at a distance is much more common in eukaryotes. Insulators(绝缘体 or boundary elements are regulatory sequences to ensure a linked promoter not responding to the activator binding
Enhancer: a given site binds regulator responsible for activating the gene. Alternative enhancer binds different groups of regulators and control expression of the same gene at different times and places in responsible to different signals. Activation at a distance is much more common in eukaryotes. Insulators (绝缘体) or boundary elements are regulatory sequences to ensure a linked promoter not responding to the activator binding
Topic 1 Conserved mechanisms of Transcriptional Regulation from/ Yeast to Mammals
Topic 1 Conserved Mechanisms of Transcriptional Regulation from Yeast to Mammals
e The basic features of gene regulation are the same in all eukaryotes, because of the similarity in their transcription and nucleosome structure e yeast is the most amenable to both genetic and biochemical dissection, and produces much of knowledge of the action of the eukaryotic repressor and activator . The typical eukaryotic activators works in a manner similar to the simplest bacterial Case e Repressors work in a variety of ways
The basic features of gene regulation are the same in all eukaryotes, because of the similarity in their transcription and nucleosome structure. Yeast is the most amenable to both genetic and biochemical dissection, and produces much of knowledge of the action of the eukaryotic repressor and activator. The typical eukaryotic activators works in a manner similar to the simplest bacterial case. Repressors work in a variety of ways
1-1 Eukaryotic activators have separate dna binding and activating functions, which are ver often on separate domains of the/protein activation domain DNA-binding DNA domain DNA-binding site Fig. 17-2 Gal4 bound to its site on DNA
1-1 Eukaryotic activators have separate DNA binding and activating functions, which are very often on separate domains of the protein. Fig. 17-2 Gal4 bound to its site on DNA
1. Gal4 is the most studied eukaryotic activator 2. Gal4 activates transcription of the galactose genes in the yeast S. cerevisae 3. Gal4 binds to four sites upstream of GAL1 and activates transcription 1000-fold in the presence of galactose 123 4 GAL 1 UASG 275bp Fig. 17-3 The regulatory sequences of the yeast GALl gene
Fig. 17-3 The regulatory sequences of the Yeast GAL1 gene. 1.Gal4 is the most studied eukaryotic activator 2.Gal4 activates transcription of the galactose genes in the yeast S. cerevisae. 3.Gal4 binds to four sites upstream of GAL1, and activates transcription 1,000-fold in the presence of galactose
The separate DNA binding and activating domains of gal4 were revealed in two complementary experiments 1. Expression of the N-terminal region (DNA-binding domain)of the activator produces a protein bound to the dna normally but did not activate transcription 2. Fusion of the c-terminal region (activation domain) of the activator to the dna binding domain of a bacterial repressor LexA activates the transcription of the reporter gene Domain swap experiment
The separate DNA binding and activating domains of Gal4 were revealed in two complementary experiments 1. Expression of the N-terminal region (DNA-binding domain) of the activator produces a protein bound to the DNA normally but did not activate transcription. 2. Fusion of the C-terminal region (activation domain) of the activator to the DNA binding domain of a bacterial repressor, LexA activates the transcription of the reporter gene. Domain swap experiment
