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THE CONTROL OF GENE EXPRESSION
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THE CONTROL OF GENE EXPRESSION

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  1. THE CONTROL OF GENE EXPRESSION

  2. THE CONTROL OF GENE EXPRESSION • GENE EXPRESSION • THE OVERALL PROCESS BY WHICH GENETIC INFORMATION FLOWS FROM GENES TO PROTEINS • PROKARYOTES ARE BEST TO STUDY FOR THIS TOPIC…WHY?? • THE LAC OPERON IN PROKARYOTES GIVES US A BETTER UNDERSTANDING OF HOW GENES ARE EXPRESSED

  3. THE CONTROL OF GENE EXPRESSION • THE LAC OPERON

  4. THE CONTROL OF GENE EXPRESSION • THE LAC OPERON • PRESENT IN E. COLI • ONLY FUNCTIONAL (TURNED ON) WHEN LACTOSE IS ABUNDANT…ENVIRONMENTAL CONDITIONS CAN IMPACT GENE EXPRESSION!!! • PARTS OF THE OPERON • OPERON • PROMOTER • OPERATOR • REPRESSOR • REGULATORY GENE

  5. THE CONTROL OF GENE EXPRESSION • THE LAC OPERON • HOW DOES IT WORK?!?!

  6. THE CONTROL OF GENE EXPRESSION • THE LAC OPERON IS NOT THE ONLY OPERON • OTHER OPERON’S MAY ALSO USE REPRESSORS; BUT THEY ALSO MAY USE… • ACTIVATORS  ??

  7. THE CONTROL OF GENE EXPRESSION • RANDOM QUESTION…YOU STARTED OUT AS A SINGLE CELL, AND THAT CELL MULTIPLIED/DIVIDED INTO A TRILLION CELLS BY THE PROCESS OF MITOSIS; BUT IF MITOSIS MAKES AN EXACT COPY OF A CELL, HOW COME EVERY CELL IN YOUR BODY ISN’T EXACTLY THE SAME???

  8. THE CONTROL OF GENE EXPRESSION • ANSWER • EVERY CELL IN YOUR BODY HAS THE EXACT SAME DNA; HOWEVER, NOT EVERY CELL EXPRESSES THE SAME DNA!!! (THIS QUESTION IS ON THE REGENTS EVERY SINGLE YEAR) • DIFFERENTIATION • THE PROCESS BY WHICH CELLS BECOME SPECIALIZED IN STRUCTURE AND FUNCTION • OCCURS BECAUSE ONLY CERTAIN GENES IN EACH PARTICULAR CELL ARE TURNED ON, WHILE OTHERS ARE TURNED OFF (HOW EXACTLY THIS HAPPENS IS UNKNOWN)

  9. THE CONTROL OF GENE EXPRESSION • DIFFERENTIATED CELLS RETAIN ALL GENETIC INFO • WHEN A CELL DIFFERENTIATES (BECOMES SPECIALIZED) IT DOESN’T LOSE DNA, JUST DOESN’T EXPRESS IT • EVIDENCE OF THIS: • CLONES • REGENERATION • NUCLEAR TRANSPLANTATION • WHAT EXACTLY ARE STEM CELLS??

  10. THE CONTROL OF GENE EXPRESSION • ATTEMPTING TO EXPLAIN THE PROCESS OF DIFFERENTATION LIES IN DISCOVERING HOW EUKARYOTIC CELLS CONTROL GENE EXPRESSION • THIS IS DIFFICULT, BECAUSE EUKARYOTIC GENOMES ARE LARGE AND COMPLEX; BUT WE SHALL DO OUR BEST!!! (VICTORY WILL BE OURS!!)

  11. THE CONTROL OF GENE EXPRESSION • MECHANISMS OF REGULATION IN EUKARYOTIC GENES • DNA PACKING • X CHROMOSOME INACTIVATION • COMPLEX PROTEIN ASSEMBLIES • ALTERNATIVE RNA SPLICING • mRNA BREAKDOWN • TRANSLATION INITIATION • PROTEIN INACTIVATION • PROTEIN BREAKDOWN

  12. THE CONTROL OF GENE EXPRESSION • DNA PACKING • HISTONES  • NUCLEOSOME  • TIGHTLY PACKED DNAPROBABLY DON’T GETEXPRESSED • HISTONES MUSTLOOSEN FOR RNAPOLYMERASE TO BIND

  13. THE CONTROL OF GENE EXPRESSION • X CHROMOSOME INACTIVATION • ONE X CHROMOSOME IS TIGHTLY PACKED/COMPACTED AND SHUT OFF ENTIRELY • ONE X CHROMOSOME IS PICKED AT RANDOM FOR EACH CELL • TORTOISE SHELL CAT 

  14. THE CONTROL OF GENE EXPRESSION • COMPLEX PROTEIN ASSEMBLIES

  15. THE CONTROL OF GENE EXPRESSION • COMPLEX PROTEIN ASSEMBLIES • TRANSCRIPTION FACTORS (TF’S)  • ENHANCERS  • SILENCERS 

  16. THE CONTROL OF GENE EXPRESSION • ALTERNATIVE RNA SPLICING • AN ORGANISM CANGET MORE THAN ONETYPE OF POLYPEPTIDEFROM A SINGLE GENE

  17. THE CONTROL OF GENE EXPRESSION • BREAKDOWN OF mRNA • mRNA GETS DEGRADED AT DIFFERENT TIMES • INITATION OF TRANSLATION • CONTROLLING WHEN TRANSLATION OCCURS • PROTEIN ACTIVATION • PROTEIN MAY BE CREATED IN A NON-FUNCTIONAL STATE • PROTEIN BREAKDOWN • PROTEINS GET DEGRADED/BROKEN DOWN AT DIFFERENT TIMES

  18. THE CONTROL OF GENE EXPRESSION • MULTIPLE MECHANISM REGULATE GENE EXPRESSION

  19. THE CONTROL OF GENE EXPRESSION • OTHER CONTROL MECHANISMS • HOMEOTIC GENES • A MASTER CONTROL GENE THAT REGULATES A BATTERY (LONG LIST) OF OTHER GENES • SIGNAL-TRANSDUCTION PATHWAYS • A SERIES OF MOLECULAR CHANGES THAT CONVERTS A SIGNAL ON A TARGET CELL’S SURFACE TO A SPECIFIC RESPONSE WITHIN THE CELL

  20. THE CONTROL OF GENE EXPRESSION • SIGNAL TRANSDUCTION PATHWAYS • TWO TYPES

  21. THE CONTROL OF GENE EXPRESSION • CANCER  • ALL INDIVIDUALS HAVE CANCER GENES WITHIN THEIR DNA (ONCOGENES) • THEY ARE NORMALLY CONTROLLED AND KEPT OFF; HOWEVER, MISTAKES CAN HAPPEN!!!

  22. THE CONTROL OF GENE EXPRESSION • CANCER • ONCOGENES • PROTO-ONCOGENES • TUMOR-SUPPRESOR GENES

  23. THE CONTROL OF GENE EXPRESSION • CANCER • DEVELOPS LATER IN LIFE, MOST OF THE TIME, BECAUSE IT TAKES AWHILE TO DEVELOP SINCE MULTIPLE MUTATIONS ARE NECESSARY

  24. THE CONTROL OF GENE EXPRESSION • CANCER • EXPOSURE TO CARCINOGENS INCREASES THE RISK OF DEVELOPING CANCER • CARCINOGEN INCREASE THE RATE OF MUTATION IN CANCER CAUSING GENES, OR INCREASE THE RATE OF CELL DIVISION • KNOW EXAMPLES??? • WHAT CAN WE DO TO PREVENT CARCINOGEN EXPOSURE??

  25. THE CONTROL OF GENE EXPRESSION • THANKS SO MUCH MR. KRAUZ FOR TEACHING US ALL THIS COOL INFO ON GENES AND STUFF, BUT HOW THE HECK DID ANYONE FIND OUT ABOUT THIS STUFF? • COME BACK TOMORROWAND I’LL TELL YOU ABOUTALL THE COOL TOYS THATSCIENTISTS GET TO PLAYWITH TO LEARN STUFFABOUT GENES!!!