Wolfgang Driever FRIAS - Dec 1, 2010

1. If you can do anything,how to make sure you do the right thing at the right time? Stem cells, pluripotency, and developmental timing in the embryo • Wolfgang Driever • FRIAS - Dec 1, 2010

2. http://www.decision-making-confidence.com/how-do-i-make-good-decisions.htmlhttp://www.decision-making-confidence.com/how-do-i-make-good-decisions.html • The act of making up your mind about something, or • a position or opinion or judgment reached after consideration • The process of selecting from several choices, products or ideas, • and taking action.

3. A simple decision making systemin 2D space and time

5. Decision making in time state reversible decision making naive time

6. Information input into decision making - generate structured decision patterns

8. Decision making in time state reversible decision making with spatial structure naive time information input

9. Problems • No stable decisions • Fuzzy pattern

10. Well defined pattern

11. Stable and well defined pattern maintained even in absence of continued information

12. What additional regulatory input may be needed to achieve this goal?

13. Decision making in time state sharpen- ing decision (integrate info over time) open state - pluri- potent reversible decision making fixed final states time promote undecided state repress decison promote and fix decision spatial information input

14. How do cells make such decisions in real life?The earliest cells in the embryo can do anything.They are pluripotent. Mouse Zebrafish Human

15. Pluripotency and decision making in the embryo 3h pluripotent 5h deciding Decision making time window 12h head trunk fate determined tail

16. Pluripotency and decision making in the embryo 3h pluripotent spatial information 5h deciding 12h Brain - Neuroectoderm head Skin - Ektoderm trunk fate determined Muscle, Organs Endo-Mesoderm germ layers tail

17. Decision making in time 12h state 3h 5h open state - pluri- potent reversible decision making sharpen- ing decision fixed final states time promote undecided state Pou5f1/Oct4 “stem cell factor” controls gene expression spatial information input

19. How to investigate the temporal sequential states during the decision making process?

20. Determine temporal profiles of genes regulated by Pou5f1:Normal wildtypes compared to Pou5f1 mutants • Compare + Pou5f1 (wildtype) against - Pou5f1 (MZspg mutants) pluripotency lineage restriction

21. A large number of genes are not activated or activated to abnormal levels in Pou5f1 mutants 1005 genes 844 genes reduced or absent without Pou5f1 increased in without Pou5f1

22. An even larger number of genes is activated prematurely or with delay: 7677 genes delayed prematurely activated hr

23. Pou5f1 targets - developmental regulators precisely timed: prematurely expressed in MZspg downregulated in MZspg downregulated in absence of Pou5f1: Sox genes, many transcriptional repressors prematurely expressed in absence of Pou5f1: differentiation genes, promoters of differentiation

24. Effect of loss of Pou5f1 on Decision making in time 12h state 3h 5h premature activation open state - pluri- potent reversible decision making sharpen- ing decision fixed final states delay time X promote undecided state Pou5f1/Oct4 “stem cell factor” controls gene expression spatial information input