1 / 31

Drosophila dorsal/ventral axis detemination

Drosophila dorsal/ventral axis detemination. How are different tissue types specified at distinct positions on the embryonic dorsal-ventral axis?. Cell fate specification at the blastoderm stage. amnio-serosa. dorsal. dorsal ectoderm. neuro-ectoderm. mesoderm. ventral. fate map.

merton
Download Presentation

Drosophila dorsal/ventral axis detemination

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Drosophila dorsal/ventral axis detemination How are different tissue types specified at distinct positions on the embryonic dorsal-ventral axis?

  2. Cell fate specification at the blastoderm stage amnio-serosa dorsal dorsal ectoderm neuro-ectoderm mesoderm ventral fate map mesoderm formation

  3. Dorsal-Ventral fate map

  4. Genes identified in a famous screen for Drosophila mutants with embryo patterning defects Torpedo Gurken

  5. Localized maternal mRNA sets up anterior and posterior poles

  6. Gurken protein specifies the Anterior-Posterior axis of the Drosophila embryo during oogenesis (Similar to EGF)

  7. 10A 1-6 gurken expression in the oocyte gurken expression in the oocyte Gurken also signals dorsal pole formation during oogenesis oocyte nucleus D D 10A 1-6 7 8 + - A P - V anterior posterior Gurken mRNA also relocalizes to anterior dorsal side. V Microtubules reorient, nucleus migrates to minus end follicle cells microtubules 8 - + -

  8. Localization of the Gurken mRNA and protein between the oocyte nucleus and the dorsal anterior cell membrane

  9. Gurken signaling inhibits production of an extracellular signal (Spätzle) by follicle cells follicle cells Torpedo = EGF receptor (in follicle cells) Gurken = Epidermal Growth Factor (EGF) Oocyte pipe expression X Ventral follicle cell Pipe (Golgi?) X Wind (ER?) X Nucleus modified from van Eeden & St.Johnston

  10. Maternal effect mutations in dorso-ventral patterning Somatic (follicle cells) ndl, pipe, wbl gd, snk, ea - serine proteases Spätzle spz - ligand Germline (nurse cells) nudel, pipe, wbl dorsal RNA Toll protein Spätzle protein Dorsal protein Toll Tl - membrane receptor tube - cytoplasmic protein pelle - ser/thr protein kinase Dorsal protein amnio serosa cact - cytoplasmic inhibitor of Dorsal nuclear translocation cactus dorsal ectoderm neuro-ectoderm dorsal dl - transcription factor (morphogen) mesoderm Dl nuclear protein

  11. dorsal and cactus mutants (maternal germline effect) dorsal dorsal mutant cactus mutant Wild type ventral A8 T1 dorsalized ventralized A7 T2 T3 A1 A2 A6 A3 A4 A5

  12. Translocation of Dorsal protein into ventral nuclei but not lateral or dorsal nuclei Wild type toll mutant cactus mutant

  13. Generation of Dorsal-Ventral polarity in Drosophila

  14. Generation of Dorsal-Ventral Polarity in Drosophila

  15. The Toll pathway in dorso-ventral pattern formation Inject wild-type cytoplasm into toll mutant eggs toll mutant ventral dorsalized local rescue dorsal ectoderm Wild type dorsal neuro-ectoderm (denticle belts) mesoderm polarity reversal

  16. Conserved pathway for regulating nuclear transport of transcription factors in Drosophila and mammals

  17. Cells with highest nuclear Dorsal levels become mesoderm

  18. Zygotically expressed genes

  19. Action of Dorsal protein in ventral cells

  20. Action of Dorsal protein in ventral cells High affinity for promoter, Not much Dorsal needed to activate

  21. Action of Dorsal protein in ventral cells Lower affinity for promoter, More Dorsal needed to activate

  22. Zygotically expressed genes

  23. Action of Dorsal protein in ventral cells Snail repression of rhomboid creates domains with distinct gene expression patterns

  24. Dorso-ventral pattern formation: summary nudel, pipe, windbeutel dorsal RNA Toll protein Spätzle protein Dorsal protein Dorsal protein dpp twist oocyte nucleus dorsal > repression of ventral fate in dorsal follicle cells ventral production of ligand > activation of Toll receptor > graded nuclear uptake of Dorsal morphogen > regulation of zygotic target gene expression > cell fates along DV axis

  25. Use of a similar regulatory system to pattern insects and vertebrates

  26. Patterns ectoderm in Drosophila Patterns mesoderm in vertebrates

  27. Gastrulation in Drosophila

  28. Schematic representation of gastrulation in Drosophila

More Related