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Gene Regulation Ch. 18

Gene Regulation Ch. 18. Precursor. Feedback inhibition. Figure 18.2. trpE gene. Enzyme 1. trpD gene. Regulation of gene expression. Enzyme 2. trpC gene. . trpB gene. . Enzyme 3. trpA gene. Tryptophan. (b). (a). Regulation of enzyme activity.

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Gene Regulation Ch. 18

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  1. Gene RegulationCh. 18

  2. Precursor Feedbackinhibition Figure 18.2 trpE gene Enzyme 1 trpD gene Regulationof geneexpression Enzyme 2 trpC gene  trpB gene  Enzyme 3 trpA gene Tryptophan (b) (a) Regulation of enzymeactivity Regulation of enzymeproduction

  3. Figure 18.3a trp operon Promoter Promoter Genes of operon DNA trpR trpE trpD trpC trpA trpB Operator Regulatory gene RNApolymerase Start codon Stop codon 3 mRNA 5 mRNA 5 E D C B A Protein Inactive repressor Polypeptide subunits that make upenzymes for tryptophan synthesis (a) Tryptophan absent, repressor inactive, operon on

  4. Figure 18.3b-1 DNA mRNA Protein Activerepressor Tryptophan (corepressor) (b) Tryptophan present, repressor active, operon off

  5. Figure 18.3b-2 DNA No RNAmade mRNA Protein Activerepressor Tryptophan (corepressor) (b) Tryptophan present, repressor active, operon off

  6. trp operon Promoter Promoter Figure 18.3 Genes of operon DNA trpE trpD trpC trpA trpR trpB Operator Regulatory gene RNApolymerase Start codon Stop codon 3 mRNA 5 mRNA 5 E D C B A Protein Inactive repressor Polypeptide subunits that make upenzymes for tryptophan synthesis (a) Tryptophan absent, repressor inactive, operon on DNA No RNAmade mRNA Protein Activerepressor Tryptophan (corepressor) (b) Tryptophan present, repressor active, operon off

  7. Figure 18.4a Regulatorygene Promoter Operator DNA DNA lacI lacZ NoRNAmade 3 mRNA RNApolymerase 5 Activerepressor Protein (a) Lactose absent, repressor active, operon off

  8. Figure 18.4b lac operon DNA lacI lacZ lacY lacA RNA polymerase 3 mRNA mRNA 5 5 -Galactosidase Permease Transacetylase Protein Inactiverepressor Allolactose(inducer) (b) Lactose present, repressor inactive, operon on

  9. Regulatorygene Promoter Operator Figure 18.4 DNA DNA lacI lacZ NoRNAmade 3 mRNA RNApolymerase 5 Activerepressor Protein (a) Lactose absent, repressor active, operon off lac operon DNA lacI lacZ lacY lacA RNA polymerase 3 mRNA mRNA 5 5 -Galactosidase Permease Transacetylase Protein Inactiverepressor Allolactose(inducer) (b) Lactose present, repressor inactive, operon on

  10. Figure 18.7 Histone tails DNA double helix Amino acidsavailablefor chemicalmodification Nucleosome(end view) (a) Histone tails protrude outward from a nucleosome Acetylated histones Unacetylated histones (b) Acetylation of histone tails promotes loose chromatinstructure that permits transcription

  11. Nucleus Master regulatorygene myoD Other muscle-specific genes Figure 18.18-1 DNA Embryonicprecursor cell OFF OFF

  12. Nucleus Master regulatorygene myoD Other muscle-specific genes Figure 18.18-2 DNA Embryonicprecursor cell OFF OFF OFF mRNA MyoD protein(transcriptionfactor) Myoblast (determined)

  13. Nucleus Master regulatorygene myoD Other muscle-specific genes Figure 18.18-3 DNA Embryonicprecursor cell OFF OFF OFF mRNA MyoD protein(transcriptionfactor) Myoblast (determined) mRNA mRNA mRNA mRNA Myosin, othermuscle proteins,and cell cycle–blocking proteins MyoD Anothertranscriptionfactor Part of a muscle fiber(fully differentiated cell)

  14. Figure 18.19a Abdomen Thorax Head 0.5 mm Dorsal Right BODYAXES Anterior Posterior Left Ventral (a) Adult

  15. 1 3 2 4 5 Follicle cell Eggdeveloping withinovarian follicle Nucleus Figure 18.19b Egg Nurse cell Unfertilized egg Eggshell Depletednurse cells Fertilization Laying of egg Fertilized egg Embryonicdevelopment Segmentedembryo 0.1 mm Hatching Body segments Larval stage (b) Development from egg to larva

  16. Figure 18.22 100 m RESULTS Anterior end Fertilization,translation ofbicoid mRNA Bicoid mRNA in matureunfertilized egg Bicoid protein inearly embryo Bicoid mRNA in matureunfertilized egg Bicoid protein inearly embryo

  17. Chapter 20 Biotechnology

  18. 2 1 3 4 Bacterium Gene inserted intoplasmid Cell containing geneof interest Figure 20.2 Bacterialchromosome Plasmid Gene of interest RecombinantDNA (plasmid) DNA ofchromosome(“foreign” DNA) Plasmid put intobacterial cell Recombinantbacterium Host cell grown in culture toform a clone of cells containingthe “cloned” gene of interest Protein expressed fromgene of interest Gene of interest Protein harvested Copies of gene Basic researchand variousapplications Basicresearchon protein Basic research on gene Gene for pestresistance insertedinto plants Gene used to alterbacteria for cleaningup toxic waste Protein dissolvesblood clots in heartattack therapy Human growthhormone treatsstunted growth

  19. 2 1 Figure 20.2a Bacterium Gene inserted intoplasmid Cell containing gene of interest Bacterialchromosome Plasmid Gene of interest RecombinantDNA (plasmid) DNA ofchromosome(“foreign” DNA) Plasmid put intobacterial cell Recombinantbacterium

  20. 3 4 Host cell grown in culture to form a clone of cells containing the “cloned” gene of interest Figure 20.2b Protein expressed fromgene of interest Gene of interest Protein harvested Copies of gene Basic researchand variousapplications Basicresearchon protein Basic research on gene Gene for pestresistance insertedinto plants Gene used to alterbacteria for cleaningup toxic waste Protein dissolvesblood clots in heartattack therapy Human growthhormone treatsstunted growth

  21. 1 Restriction site 5 3 Figure 20.3-1 GAATTC DNA CTTAAG 5 3 Restriction enzymecuts sugar-phosphatebackbones. 5 3 3 5 AATTC G CTTAA G 5 Sticky end 3 5 3

  22. 1 2 Restriction site 5 3 Figure 20.3-2 GAATTC DNA CTTAAG 5 3 Restriction enzymecuts sugar-phosphatebackbones. 5 3 3 5 AATTC G CTTAA G 5 Sticky end 3 5 3 5 3 AATTC G G CTTAA DNA fragment addedfrom another moleculecut by same enzyme.Base pairing occurs. 3 5 5 3 5 3 5 3 G AATT C G AATT C C TTAA G G C TTAA 3 5 3 5 5 3 One possible combination

  23. 1 2 3 Restriction site 5 3 Figure 20.3-3 GAATTC DNA CTTAAG 5 3 Restriction enzymecuts sugar-phosphatebackbones. 5 3 3 5 AATTC G CTTAA G 5 Sticky end 3 5 3 5 3 AATTC G G CTTAA DNA fragment addedfrom another moleculecut by same enzyme.Base pairing occurs. 3 5 5 3 5 3 5 3 G AATT C G AATT C C TTAA G G C TTAA 3 5 3 5 5 3 One possible combination DNA ligaseseals strands 5 3 3 5 Recombinant DNA molecule

  24. TECHNIQUE Hummingbird cell Bacterial plasmid lacZ gene ampR gene Figure 20.4 Restrictionsite Sticky ends Gene ofinterest Humming-bird DNAfragments Recombinant plasmids Nonrecombinant plasmid Bacteria carryingplasmids RESULTS Colony carrying recombinantplasmidwith disruptedlacZ gene Colony carrying non-recombinant plasmidwith intact lacZ gene One of manybacterialclones

  25. Hummingbird cell TECHNIQUE Figure 20.4a-1 Bacterial plasmid lacZ gene ampR gene Restrictionsite Sticky ends Gene ofinterest Humming-bird DNAfragments

  26. Hummingbird cell TECHNIQUE Figure 20.4a-2 Bacterial plasmid lacZ gene ampR gene Restrictionsite Sticky ends Gene ofinterest Humming-bird DNAfragments Recombinant plasmids Nonrecombinant plasmid

  27. Hummingbird cell TECHNIQUE Figure 20.4a-3 Bacterial plasmid lacZ gene ampR gene Restrictionsite Sticky ends Gene ofinterest Humming-bird DNAfragments Recombinant plasmids Nonrecombinant plasmid Bacteria carryingplasmids

  28. Figure 20.4b Bacteria carryingplasmids RESULTS Colony carrying recombinantplasmidwith disruptedlacZ gene Colony carrying non-recombinant plasmidwith intact lacZ gene One of manybacterialclones

  29. Figure 20.8a 5 3 TECHNIQUE Targetsequence Genomic DNA 3 5

  30. 1 2 3 5 3 Figure 20.8b Denaturation 3 5 Annealing Cycle 1yields2molecules Primers Extension Newnucleo-tides

  31. Figure 20.8c Cycle 2yields4molecules

  32. Figure 20.8d Cycle 3yields 8molecules;2 molecules(in white boxes)match targetsequence

  33. 1 2 3 3 5 TECHNIQUE Targetsequence Figure 20.8 5 Genomic DNA 3 5 Denaturation 3 5 3 Annealing Cycle 1yields2molecules Primers Extension Newnucleotides Cycle 2yields4molecules Cycle 3yields 8molecules;2 molecules(in white boxes)match targetsequence

  34. 1 2 TECHNIQUE Powersource Figure 20.9a Mixture ofDNA mol-ecules ofdifferentsizes   Anode Cathode Wells Gel Powersource   Longermolecules Shortermolecules

  35. Figure 20.9b RESULTS

  36. (b) Electrophoresis of restrictionfragments from normal andsickle-cell alleles Figure 20.10b Sickle-cellallele Normalallele Largefragment 376 bp 201 bp 175 bp

  37. 2 1 3 TECHNIQUE Figure 20.19a Mammarycell donor Egg cell donor Eggcell fromovary Nucleusremoved Cells fused Culturedmammarycells Nucleus frommammary cell

  38. 4 5 6 Nucleus frommammary cell Figure 20.19b Grown in culture Early embryo Implanted in uterusof a third sheep Surrogatemother Embryonicdevelopment RESULTS Lamb (“Dolly”) geneticallyidentical to mammary cell donor

  39. 2 1 3 4 Cloned gene Figure 20.23 Insert RNA version of normal alleleinto retrovirus. Viral RNA Let retrovirus infect bone marrow cellsthat have been removed from thepatient and cultured. Retroviruscapsid Viral DNA carrying the normalallele inserts into chromosome. Bonemarrowcell frompatient Bonemarrow Inject engineeredcells into patient.

  40. TECHNIQUE Agrobacterium tumefaciens Figure 20.26 Tiplasmid Site whererestrictionenzyme cuts T DNA DNA withthe geneof interest RESULTS RecombinantTi plasmid Plant with new trait

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