March 3, 2010

1. March 3, 2010 Introduction to development Gene expression

3. What cellular functions are needed to carry out development?

4. What cellular functions are needed to carry out development? Divide Grow Differentiate Die Move Adhere Secrete Signal Cell biological properties need to be coordinated in space and time

5. Where is the “program” for development encoded?

6. Where is the “program” for development encoded? In the genes

7. Why do different cells behave differently?

8. Why do different cells behave differently? Have different genes? Have different histories? Experience different environments? Chance? Have different gene expression states?

9. Why do different cells behave differently? Have different genes? Have different histories? Experience different environments? Chance? Have different gene expression states?

10. 05_02_DNA.jpg

11. 05_10_Genes_info.jpg Genes Carry out functions

12. Steps in gene expression 07_37_Protein.produc.jpg

13. Regulation of gene expression 08_03_control.steps.jpg mRNA localization control (tether mRNA to localized proteins) mRNA turnover control (microRNAs) Protein turnover control (ubiquitylation and proteasome digestion) Protein localization control

14. Regulation of gene expression 08_03_control.steps.jpg mRNA localization control (tether mRNA to localized proteins) mRNA turnover control (microRNAs) Protein turnover control (ubiquitylation and proteasome digestion) Protein localization control

15. Regulation of transcription: Parts of a gene coding strand

16. Regulation of transcription 08_13_gene.activation.jpg

17. Transcription factors

18. 05_24_Chromatin pack.jpg Nucleosomes (histones) package DNA

19. Histone modifications affect gene expression 05_30_histone tails.jpg Can affect recruitment of transcription factors to promoter

20. Some transcription factors affect histones 08_14_chromatin.struc.jpg

21. Multiple transcription factors regulate most genes 08_15_Reg. proteins.jpg

22. Modularity of the Drosophila even-skipped promoter 08_18_reporter.gene.jpg

23. Coordinated regulation of multiple genes Developmental functions

24. Signals can regulate activity of transcription factors

25. Maintaining gene expression states 08_23_cell.memory.jpg (a positive feedback loop)

26. Maintaining gene expression states 08_24_chromatin.state.jpg

27. The histone code also needs to be maintained in daughter cells

28. Maintaining gene expression states – DNA methylation

29. How does one monitor which genes a particular cell expresses?

30. Southern blot 10_14_1_Southrn.blotting.jpg

31. 10_14_2_Southrn.blotting.jpg Southern blot – DNA on blot Northern blot – RNA on blot

32. Northern blot hybridization (tests one gene at a time)

33. In situ hybridization of developing flowers with ARF6 probe

34. Rb-Related expression in Arabidopsis embryos by in situ hybridization From Wildwater et al., Cell 123: 1337-1349 (2005)

35. 08_18_reporter.gene.jpg Promoter:reporter fusion gene in a transgenic fly embryo

36. PARF6::ARF6::GUS fusion expression in flowers and ovules Promoter:protein:reporter fusion gene – reveals protein location

37. Immunolocalization of Snail and Twist proteins in Drosophila embryos anti-Snail anti-Twist Kosman et al., Science 254: 118-122 (1991)

38. Utility of looking at expression of single genes at a time: Markers of cell type, differentiation Visualization of regulatory events Utility of looking at expression of many genes at once: Global view of tissue identity Comparing different tissues or states Global view of regulatory events