1. Ch. 15 Warm-Up Compare DNA methylation and histone acetylation.
What is the role of activators vs. repressors? Where do they bind to?
List the components found in a eukaryotic transcription initiation complex.
What is the function of miRNAs and siRNAs?

2. Ch. 16 Warm-Up
List and describe the 3 processes that are involved in transforming a zygote.
Compare oncogenes, proto-oncogenes, and tumor suppresor genes.
What are the roles of the ras gene and the p53 gene?

3. Development, Stem Cells & Cancer
Chapter 16

4. What you must know:
How timing and coordination of specific events are regulated in normal development, including pattern formation and induction.
The role of gene regulation in embryonic development and cancer.

5. A program of differential gene expression leads to the different cell types in a multicellular organism
Chapter 16.1

6. Embryonic Development: Zygote  Organism
Cell Division: large # identical cells through mitosis
Cell Differentiation: cells become specialized in structure & function
Morphogenesis: “creation of form” – organism’s shape

7. Cytoplasmic determinants: maternal substances in egg distributed unevenly in early cells of embryo

8. Induction: cells triggered to differentiate
Cell-Cell Signals: molecules produced by one cell influences neighboring cells
Eg. Growth factors

9. Determination: irreversible series of events that lead to cell differentiation

10. Regulatory genes and transcription factors direct cell differentiation

11. Role of Apoptosis Most of the embryonic cells are produced in excess
Cells will undergo apoptosis (programmed cell death) to sculpture organs and tissues
Carried out by caspase proteins

12. Apoptosis of a human white blood cell

13. Pattern formation: setting up the body plan (head, tail, L/R, back, front) as a result of cytoplasmic determinants and inductive signals

14. Morphogens: uneven distribution of substances that establish an embryo’s axes

15. Homeotic Genes: master control genes that control pattern formation (eg. Hox genes)
Mutations in homeotic genes cause misplacement of structures.

16. Evolving Switches, Evolving Bodies
HHMI Short Film

17. Pitx1 Gene = Homeotic/Hox Gene
Stickleback Fish
Humans
Development of pelvic bone
Development of anterior structures, brain, structure of hindlimb
Mutation may cause clubfoot, polydactyly (extra fingers/toes), upper limb deformities

18. Chapter 16.2
Cloning of organisms showed that differentiated cells could be “reprogrammed” and ultimately lead to the production of stem cells

19. Cloning Organisms
Nuclear transplantation: nucleus of egg is removed and replaced with nucleus of body cell

20. Nuclear Transplantation

21. Problems with Reproductive Cloning
Cloned embryos exhibited various defects
DNA of fully differentiated cells have epigenetic changes

22. Stem Cells
Stem cells: can reproduce itself indefinitely and produce other specialized cells
Zygote = totipotent (any type of cell)
Embryonic stem (ES) cells = pluripotent (many cell types)
Adult stem cells = multipotent (a few cell types) or induced pluripotent, iPS (“deprogrammed” to be pluripotent)

23. Embryonic vs. Adult stem cells

24. Using stem cells for disease treatment

25. Abnormal regulation of genes that affect the cell cycle can lead to cancer
Chapter 16.3

26. Control of Cell Cycle: Proto-oncogene = stimulates normal cell growth
Tumor-suppressor gene = inhibits cell division
Mutations in these genes can lead to cancer

27. Proto-Oncogene Oncogene
Gene that stimulates normal cell growth & division
Mutation in proto-oncogene
Cancer-causing gene
Effects:
Increase product of proto- oncogene
Increase activity of each protein molecule produced by gene

28. Proto-oncogene  Oncogene

29. Genes involved in cancer:
Ras gene: proto-oncogene
Stimulates cell cycle
Mutations of ras occurs in 30% of cancers
p53 gene: tumor-suppressor gene
Functions: halt cell cycle for DNA repair, turn on DNA repair, activate apoptosis (cell death)
Mutations of p53 in 50+% of cancers

30. Ras gene

31. p53 gene

32. Cancer results when mutations accumulate (5-7 changes in DNA)
Active oncogenes + loss of tumor-suppressor genes
The longer we live, the more likely that cancer might develop

35. Summary
Embryonic development occurs when gene regulation proceeds correctly
Cancer occurs when gene regulation goes awry