Gene Regulation Ch. 18

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

Figure 18.3a Promoter DNA Regulatory gene mRNA trpR 5 3 Protein Inactive repressor RNA polymerase Promoter trp operon Genes of operon Operator mRNA 5 Start codonStop codon trpEtrpDtrpC trpB trpA EDCBA Polypeptide subunits that make up enzymes for tryptophan synthesis (a) Tryptophan absent, repressor inactive, operon on

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

Figure 18.3b-2 (b) Tryptophan present, repressor active, operon off DNA mRNA Protein Tryptophan (corepressor) Active repressor No RNA made

Promoter DNA Regulatory gene mRNA trpR 5 3 Protein Inactive repressor RNA polymerase Promoter trp operon Genes of operon Operator mRNA 5 Start codonStop codon trpEtrpDtrpC trpB trpA EDCBA Polypeptide subunits that make up enzymes for tryptophan synthesis (a) Tryptophan absent, repressor inactive, operon on (b) Tryptophan present, repressor active, operon off DNA mRNA Protein Tryptophan (corepressor) Active repressor No RNA made Figure 18.3

Figure 18.4a (a) Lactose absent, repressor active, operon off Regulatory gene Promoter Operator DNA lacZ lac I DNA mRNA 5 3 No RNA made RNA polymerase Active repressor Protein

Figure 18.4b (b) Lactose present, repressor inactive, operon on lac I lac operon lacZlacYlacADNA mRNA 5 3 Protein mRNA 5 Inactive repressor RNA polymerase Allolactose (inducer)  -Galactosidase PermeaseTransacetylase

(a) Lactose absent, repressor active, operon off (b) Lactose present, repressor inactive, operon on Regulatory gene Promoter Operator DNA lacZlac I DNA mRNA 5 3 No RNA made RNA polymerase Active repressor Protein lac operon lacZlacYlacADNA mRNA 5 3 Protein mRNA 5 Inactive repressor RNA polymerase Allolactose (inducer)  -Galactosidase PermeaseTransacetylase Figure 18.4

Figure 18.7 Amino acids available for chemical modification Histone tails DNA double helix Nucleosome (end view) (a) Histone tails protrude outward from a nucleosome Unacetylated histones Acetylated histones (b) Acetylation of histone tails promotes loose chromatin structure that permits transcription

Nucleus Embryonic precursor cell DNA Master regulatory gene myoD OFF Other muscle-specific genes Figure

Nucleus Embryonic precursor cell Myoblast (determined) DNA Master regulatory gene myoD OFF mRNA Other muscle-specific genes MyoD protein (transcription factor) Figure

Nucleus Embryonic precursor cell Myoblast (determined) Part of a muscle fiber (fully differentiated cell) DNA Master regulatory gene myoD OFF mRNA Other muscle-specific genes MyoD protein (transcription factor) mRNA MyoD Another transcription factor Myosin, other muscle proteins, and cell cycle– blocking proteins Figure

Figure 18.19a Head Thorax Abdomen 0.5 mm BODY AXES Anterior Left Ventral Dorsal Right Posterior (a) Adult

Figure 18.19b Egg developing within ovarian follicle Follicle cell Nucleus Nurse cell Egg Unfertilized egg Depleted nurse cells Egg shell Fertilization Laying of egg Fertilized egg Embryonic development Segmented embryo Body segments Hatching 0.1 mm Larval stage (b) Development from egg to larva

Figure Bicoid mRNA in mature unfertilized egg Fertilization, translation of bicoid mRNA Anterior end 100  m Bicoid protein in early embryo RESULTS

LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson © 2011 Pearson Education, Inc. Lectures by Erin Barley Kathleen Fitzpatrick Biotechnology Chapter 20

Figure 20.2 Bacterium Bacterial chromosome Plasmid 2134 Gene inserted into plasmid Cell containing gene of interest Recombinant DNA (plasmid) Gene of interest Plasmid put into bacterial cell DNA of chromosome (“foreign” DNA) Recombinant bacterium Host cell grown in culture to form a clone of cells containing the “cloned” gene of interest Gene of interest Protein expressed from gene of interest Protein harvested Copies of gene Basic research and various applications Basic research on protein Basic research on gene Gene for pest resistance inserted into plants Gene used to alter bacteria for cleaning up toxic waste Protein dissolves blood clots in heart attack therapy Human growth hormone treats stunted growth

Figure 20.2a Bacterium Bacterial chromosome Plasmid 21 Gene inserted into plasmid Cell containing gene of interest Recombinant DNA (plasmid) Gene of interest Plasmid put into bacterial cell DNA of chromosome (“foreign” DNA) Recombinant bacterium

Figure 20.2b Host cell grown in culture to form a clone of cells containing the “cloned” gene of interest Gene of interest Protein expressed from gene of interest Protein harvested Copies of gene Basic research and various applications 34 Basic research on protein Basic research on gene Gene for pest resistance inserted into plants Gene used to alter bacteria for cleaning up toxic waste Protein dissolves blood clots in heart attack therapy Human growth hormone treats stunted growth

Figure Restriction enzyme cuts sugar-phosphate backbones. Restriction site DNA Sticky end GAATTC CTTAAG CTTAA G AATTC G

Figure One possible combination DNA fragment added from another molecule cut by same enzyme. Base pairing occurs. Restriction enzyme cuts sugar-phosphate backbones. Restriction site DNA Sticky end GAATTC CTTAAG CTTAA G AATTC G G G CTTAA G G G G AATT C C TTAA

Figure Recombinant DNA molecule One possible combination DNA ligase seals strands DNA fragment added from another molecule cut by same enzyme. Base pairing occurs. Restriction enzyme cuts sugar-phosphate backbones. Restriction site DNA Sticky end GAATTC CTTAAG CTTAA G AATTC G G G CTTAA G G G G AATT C C TTAA

Figure 20.4 Bacterial plasmid TECHNIQUE RESULTS amp R gene lacZ gene Restriction site Hummingbird cell Sticky ends Gene of interest Humming- bird DNA fragments Recombinant plasmidsNonrecombinant plasmid Bacteria carrying plasmids Colony carrying non- recombinant plasmid with intact lacZ gene Colony carrying recombinant plasmid with disrupted lacZ gene One of many bacterial clones

Figure 20.4a-1 Bacterial plasmid TECHNIQUE amp R gene lacZ gene Restriction site Hummingbird cell Sticky ends Gene of interest Humming- bird DNA fragments

Figure 20.4a-2 Bacterial plasmid TECHNIQUE amp R gene lacZ gene Restriction site Hummingbird cell Sticky ends Gene of interest Humming- bird DNA fragments Recombinant plasmidsNonrecombinant plasmid

Figure 20.4a-3 Bacterial plasmid TECHNIQUE amp R gene lacZ gene Restriction site Hummingbird cell Sticky ends Gene of interest Humming- bird DNA fragments Recombinant plasmidsNonrecombinant plasmid Bacteria carrying plasmids

Figure 20.4b RESULTS Bacteria carrying plasmids Colony carrying non- recombinant plasmid with intact lacZ gene Colony carrying recombinant plasmid with disrupted lacZ gene One of many bacterial clones

Figure 20.8a Genomic DNA Target sequence TECHNIQUE

Denaturation Annealing Extension Primers New nucleo- tides Cycle 1 yields 2 molecules Figure 20.8b

Figure 20.8c Cycle 2 yields 4 molecules

Figure 20.8d Cycle 3 yields 8 molecules; 2 molecules (in white boxes) match target sequence

Figure 20.8 Genomic DNA Target sequence Denaturation Annealing Extension Primers New nucleotides Cycle 1 yields 2 molecules Cycle 2 yields 4 molecules Cycle 3 yields 8 molecules; 2 molecules (in white boxes) match target sequence TECHNIQUE

Figure 20.9a Mixture of DNA mol- ecules of different sizes Power source Longer molecules Cathode Anode Wells Gel Shorter molecules TECHNIQUE 2     1

Figure 20.9b RESULTS

Figure 20.10b Large fragment Normal allele Sickle-cell allele 201 bp 175 bp 376 bp (b) Electrophoresis of restriction fragments from normal and sickle-cell alleles

Figure 20.19a Mammary cell donor 213 TECHNIQUE Cultured mammary cells Egg cell from ovary Egg cell donor Nucleus removed Cells fused Nucleus from mammary cell

456 RESULTS Grown in culture Implanted in uterus of a third sheep Embryonic development Nucleus from mammary cell Early embryo Surrogate mother Lamb (“Dolly”) genetically identical to mammary cell donor Figure 20.19b

Figure Cloned gene Retrovirus capsid Bone marrow cell from patient Viral RNA Bone marrow Insert RNA version of normal allele into retrovirus. Let retrovirus infect bone marrow cells that have been removed from the patient and cultured. Viral DNA carrying the normal allele inserts into chromosome. Inject engineered cells into patient.

Figure Plant with new trait RESULTS TECHNIQUE Ti plasmid Site where restriction enzyme cuts DNA with the gene of interest Recombinant Ti plasmid T DNA Agrobacterium tumefaciens