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Lecture 6

Lecture 6. Anterior posterior axis formation-the posterior signal Anterior posterior axis formation-down the hierarchy. Lab 3. 208 or 210: P{hsp ftz D 273-303 ry + } 226: P{hsp ftz 3-413 ry + }. Lab 5. 166 refers to embryos laid by DH502 females crossed with DH302 males.

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Lecture 6

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  1. Lecture 6 • Anterior posterior axis formation-the posterior signal • Anterior posterior axis formation-down the hierarchy

  2. Lab 3 208 or 210: P{hsp ftz D273-303 ry+} 226: P{hsp ftz 3-413 ry+}

  3. Lab 5 166 refers to embryos laid by DH502 females crossed with DH302 males. 167 refers to embryos laid by DH502 females crossed with DH301 males. Consult Hyduk and Percival-Smith for the genotypes associated with the above strain names. See Table 1 and Figure 5.

  4. The mutant allele used for the engrailed and wingless experiments was ftz13.

  5. Pole cell transplantation Mosaic analysis Cellular Blastoderm Egg chamber

  6. Example pipe (pip) Toll (Tll) What cells, follicle or germ-line, are pipe and Toll required in?

  7. Pole cell transplantation Mosaic analysis OvoD No eggs

  8. Pole cell transplantation Mosaic analysis OvoD Wild type

  9. Pole cell transplantation Mosaic analysis OvoD Wild type Wild type Active egg chamber get eggs produced

  10. Toll

  11. pipe

  12. Posterior signal

  13. Three classes of maternal effect phenotypes Nusslein-Volhard et al., Science 238, 1675-1681

  14. Nusslein-Volhard et al., Science 238, 1675-1681

  15. What was done to show that nanos was the best candidate to encode the posterior signal?

  16. Pole cell formation

  17. Injection of oocyte cytoplasm nanos

  18. Injection of nurse cell cytoplasm nanos

  19. Injection of stage 10 cytoplasm

  20. Nanos isolation expression Wang and Lehmann Cell 66, 637-647

  21. Nanos isolation localization Wang and Lehmann Cell 66, 637-647

  22. Nanos isolation rescue Wang and Lehmann Cell 66, 637-647

  23. Nanos and maternal Hunchback expression Nanos Hunchback

  24. Expression of Hunchback from maternal mRNA

  25. Nanos Maternal Hunchback expression

  26. Larvae lacking both maternal and zygotic hb exhibit a stronger phenotype hb/hb Irish et al., Nature 338, 646-648

  27. Larvae lacking both maternal and zygotic hb exhibit a stronger phenotype hb/hb Pole cell transplantation hb- OvoD mat hb- hb/hb hb+ Irish et al., Nature 338, 646-648

  28. Larvae lacking both maternal and zygotic hb exhibit a stronger phenotype hb/hb hb- mat hb- Irish et al., Nature 338, 646-648

  29. Maternal Hunchback is dispensable for normal development hb/hb hb- mat hb- hb+ Irish et al., Nature 338, 646-648

  30. Nanos phenotype Irish et al., Nature 338, 646-648

  31. Nanos has no role when mat hb is removed Pole cell transplantation OvoD hb+ hb/hb nos/nos mat nos- hb- Irish et al., Nature 338, 646-648

  32. Two polar centers regulate Hunchback expression Wharton and Struhl Cell 67, 955-967

  33. Nanos regulatory sequences in the 3’ UTR of mat hb Wharton and Struhl Cell 67, 955-967

  34. Hunchback expression Wharton and Struhl Cell 67, 955-967

  35. Nanos represses bicoid translation mRNA protein Wang and Lehmann Cell 66, 637-647

  36. What Nanos and Pumilio do to suppress Hunchback Gilbert Developmental Biology 7th ed

  37. Microtubules and the transport of Nanos and Bicoid mRNA Gilbert Developmental Biology 7th ed

  38. Hunchback lacks anterior segments Nusslein-Volhard and Wieschaus 1980 Nature 287, 795

  39. Gap proteins Transcription factors Hunchback is a morphogen Delineate blocks of pattern along the A-P axis Gap information used to set up the striped expression of pair-rule genes

  40. Expression of some Gap proteins HB GTa TLLa Kr Kni GTp TLLp 0% 100% egg length

  41. Posterior signal is permissive because the terminal protein Tailless supresses GT expression. The termini provide polarity. HB TLLa GT Kni Kr Kni GT TLLp 0% 100% egg length

  42. Hunchback gradient and the regulation of gap genes HB Kr Kni GTp 0% 100% egg length

  43. Hunchback gradient and the regulation of gap genes Regulatory rules medium [HB] activates Kr medium [HB] represses Kni low [HB] represses gtp

  44. Outcome of the regulatory rules HB Kr Kni GTp 0% 100% egg length

  45. Expression of FTZ and EVE Lawrence The making of a fly

  46. Eve stripe 2 regulatory element Gilbert Developmental Biology 7th ed

  47. Stripe two element expression lacZ

  48. HB BCD GTa Kr 0% 100% egg length

  49. HB EVE stripe two BCD GTa Kr 0% 100% egg length

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