* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Oc - TUM
Gene expression profiling wikipedia , lookup
Gene desert wikipedia , lookup
Molecular cloning wikipedia , lookup
RNA silencing wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Epitranscriptome wikipedia , lookup
List of types of proteins wikipedia , lookup
Transcription factor wikipedia , lookup
Non-coding RNA wikipedia , lookup
Cre-Lox recombination wikipedia , lookup
Community fingerprinting wikipedia , lookup
RNA polymerase II holoenzyme wikipedia , lookup
Genome evolution wikipedia , lookup
Genetic engineering wikipedia , lookup
Deoxyribozyme wikipedia , lookup
Non-coding DNA wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Histone acetylation and deacetylation wikipedia , lookup
Gene expression wikipedia , lookup
Gene regulatory network wikipedia , lookup
Eukaryotic transcription wikipedia , lookup
Molecular evolution wikipedia , lookup
Endogenous retrovirus wikipedia , lookup
Promoter (genetics) wikipedia , lookup
Silencer (genetics) wikipedia , lookup
Einführung in die Genetik Prof. Dr. Kay Schneitz (EBio Pflanzen) http://plantdev.bio.wzw.tum.de [email protected] Twitter: @PlantDevTUM, #genetikTUM FB: Plant Development TUM Prof. Dr. Claus Schwechheimer (PlaSysBiol) http://wzw.tum.de/sysbiol [email protected] Einführung in die Genetik - Inhalte 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Einführung Struktur von Genen und Chromosomen Genfunktion Transmission der DNA während der Zellteilung Vererbung von Einzelgenveränderungen Genetische Rekombination (Eukaryonten) Genetische Rekombination (Bakterien/Viren) Rekombinante DNA-Technologie Kartierung/Charakterisierung ganzer Genome Genmutationen: Ursache und Reparatur Veränderungen der Chromosomen Genetische Analyse biologischer Prozesse Transposons bei Eukaryonten Regulation der Genexpression Regulation der Zellzahl - Onkogene 16. 10. 12 23. 10. 12 30. 10. 12 06. 11. 12 13. 11. 12 20. 11. 12 27. 11. 12 04. 12. 12 11. 12. 12 18. 12. 12 08. 01. 13 15. 01. 13 22. 01. 13 29. 01. 13 05. 02. 13 KS KS KS KS KS KS KS CS CS CS CS CS CS KS CS Transposons Genetics 13 Summary • • Discovery of transposons (Mais) • • • Replicative vs. conservative transposition • Experiment (retrotransposons, RNA intermediate) • • • • DNA transposons (P elements, Ac/Ds) • • Plant genomes (genome size and transposons) Structure of transposons (simple vs. composite transposons) Transposons and bacterial antibiotic resistance RNA transposons, retrotransposons (retrovirus, gag, pol, env) Excision (short DNA repeat = footprint) Transposons and genome evolution Human genome (LINE and SINE RNA transposons; DNA transposons) Safe havens (intergenic regions, introns, rRNA genes, gene promoters) Regulation of Gene Expression Genetics 14 Topics Gene regulation in bacteria Genetic analysis of gene induction Basic logical and molecular principles of genetic switches Gene regulation in eukaryotes Chromatin Overview of transcription E. coli: Initiation E. coli: The promoter Eukaryotes: Initiation Why? Gene regulation in bacteria Genetic Switches An/Ausschalter Positive vs negative regulation Modular functionality: e.g., allosteric effectors Model: the lac system of E. coli Induction of ß-galactosidase by the disaccharide lactose Francois Jacob André Lwoff Jacques Monod The inducer: lactose Simplified lac operon model No lactose present Lactose present Genetic dissection of lac system Genetic components I Y P Z O A I-, Is YPZOc A- Generating partial diploids in E. coli mutants: Synthesis of ß-galactosidase/permease c O mutants: Synthesis of ß-galactosidase/permease c O mutants: Synthesis of ß-galactosidase/permease c O mutants: Synthesis of ß-galactosidase/permease c O mutants: Synthesis of ß-galactosidase/permease c O mutants: Synthesis of ß-galactosidase/permease c O c O is a constitutive mutation mutants: Synthesis of ß-galactosidase/permease c O c O is a constitutive mutation Operator (O) is cis-acting Interpretation Interpretation Operators are cis-acting mutants: Synthesis of ßgalactosidase/permease I mutants: Synthesis of ßgalactosidase/permease I mutants: Synthesis of ßgalactosidase/permease I mutants: Synthesis of ßgalactosidase/permease I mutants: Synthesis of ßgalactosidase/permease I mutants: Synthesis of ßgalactosidase/permease I Repressor (I) is trans-acting Interpretation Interpretation Repressors are trans-acting alleles: Synthesis of ßgalactosidase/permease s I alleles: Synthesis of ßgalactosidase/permease s I alleles: Synthesis of ßgalactosidase/permease s I alleles: Synthesis of ßgalactosidase/permease s I alleles: Synthesis of ßgalactosidase/permease s I s I : repressor is hyperactive Interpretation Interpretation Repressor contains a lactose-binding site Lactose present Genetic analysis: I vs O • both elements act in repressing lac operon • they fundamentally differ in their mode of action (cis vs trans mode) • reveals important aspects of the molecular mechanism of lac repression Control of lac system: Lactose vs glucose Catabolite repression of the lac operon Catabolite repression of the lac operon Glucose is a catabolite of lactose cAMP/CAP complex is an activator of transcription Control of the lac operon Molecular anatomy of the genetic switch The operator is a specific DNA sequence The operator is a specific DNA sequence Very specific sequence! One base change enough to eliminate O function Many DNA binding sites are symmetrical Binding of CAP bends DNA Binding of CAP bends DNA Recognition of specific CAP-binding site CAP/RNA pol: Binding sites Helix-turn-helix is a common DNA-binding motif Helix-turn-helix is a common DNA-binding motif Specific contacts with bases in major groove Helix-turn-helix is a common DNA-binding motif Dimers Specific contacts with bases in major groove AA side chains determine specificity of DNA binding Homeodomain Repression vs activation Genetic switches are often part of a cascade mechanism A TF B C • Summary • • • • • Cells respond to intrinsic and extrinsic signals by modulating transcriptional control of certain genes Gene activity is the result of the function of cis- and trans-acting factors Trans-acting proteins react to environmental signals by using built-in sensors that continually monitor cellular conditions Coordinated gene regulation in bacteria • gene are often clustered into operons on the chro and transcribed together into multigenic mRNAs • one cluster of regulatory sites per operon is sufficient to regulate expression of several genes Negative vs positive regulation • repressor proteins bind to DNA at operator site thereby blocking transcription (e.g., lac operon) • activator proteins activate transcription by binding to DNA at the promoter region (e.g., cAMP/CAP regulation of lac operon) Molecular anatomy of genetic switch • regulatory proteins have DNA-binding domains (e.g., HLH) and protein-protein interaction domains (modular • specificity of gene regulation depends on specific protein-DNA interactions mediated by the chemical interactions between aa side chains and chemical groups of DNA bases Gene regulation in eukaryotes Drosophila: MSL complex and dosage compensation Overview of transcriptional regulation Eukaryotic promoter The yeast GAL system The transcriptional activator Gal4 The transcriptional activator Gal4 TF: sequence-specific binding to regions outside the promoters of target genes TFs: Modular Proteins Transcriptional activators and the transcription machinery Enhancer action: Mechanism Enhancer action: Mechanism Cooperativity Synergism Disperse distribution of enhancer elements DPP of Drosophila kb Modular and combinatorial control eve TATA lacZ Chromatin Chromatin dynamics Chromatin remodeling e.g., by SWI-SNF complex Histone modifications and the histone code Tup1, a histone deacetylase from yeast, is a corepressor Linking TFs and chromatin dynamics Enhanceosome Enhanceosome Cooperativity Synergism Enhanceosome Cooperativity Synergism • Summary• • Eukaryotic gene regulation resembles bacterial gene regulation • • trans-acting factors binding to cis-regulatory elements on the DNA this regulatory factors determine the level of transcription by regulating the binding of RNA pol II to the promoter of a gene Enhancers/UAS • cis-regulatory elements, possibly located quite far away (>10-50kb) from promoter • • combinatorial interactions among different transcription factors enhanceosome: complexes of regulatory proteins that interact in cooperative and synergistic fashion --> high levels of transcription through recruitment of RNA pol II Gene regulation and chromatin • • • eukaryotic genes are packed in chromatin • histone code: pattern of posttranslational modifications of histone tails (acetylation, methylation, phosphorylation etc). • histone code is an epigenetic mark involved in nucleosome positioning and chromatin condensation that can be altered by TFs • Tfs recruit for example ATP-dependent chromatin remodelers (e.g., SWI-SNF) activation/repression requires specific modifications to chromatin genes are mostly turned off and kept silent in part by nucleosomes and condensed chromatin THE END