Book contents
- Frontmatter
- Contents
- Preface
- CHAPTER ONE CELL LINEAGE VS. INTERCELLULAR SIGNALING
- CHAPTER TWO THE BRISTLE
- CHAPTER THREE BRISTLE PATTERNS
- CHAPTER FOUR ORIGIN AND GROWTH OF DISCS
- CHAPTER FIVE THE LEG DISC
- CHAPTER SIX THE WING DISC
- CHAPTER SEVEN THE EYE DISC
- CHAPTER EIGHT HOMEOSIS
- EPILOGUE
- APPENDIX ONE Glossary of Protein Domains
- APPENDIX TWO Inventory of Models, Mysteries, Devices, and Epiphanies
- APPENDIX THREE Genes That Can Alter Cell Fates Within the (5-Cell) Mechanosensory Bristle Organ
- APPENDIX FOUR Genes That Can Transform One Type of Bristle Into Another or Into a Different Type of Sense Organ
- APPENDIX FIVE Genes That Can Alter Bristle Number by Directly Affecting SOP Equivalence Groups or Inhibitory Fields
- APPENDIX SIX Signal Transduction Pathways: Hedgehog, Decapentaplegic, and Wingless
- APPENDIX SEVEN Commentaries on the Pithier Figures
- References
- Index
CHAPTER SIX - THE WING DISC
Published online by Cambridge University Press: 03 December 2009
- Frontmatter
- Contents
- Preface
- CHAPTER ONE CELL LINEAGE VS. INTERCELLULAR SIGNALING
- CHAPTER TWO THE BRISTLE
- CHAPTER THREE BRISTLE PATTERNS
- CHAPTER FOUR ORIGIN AND GROWTH OF DISCS
- CHAPTER FIVE THE LEG DISC
- CHAPTER SIX THE WING DISC
- CHAPTER SEVEN THE EYE DISC
- CHAPTER EIGHT HOMEOSIS
- EPILOGUE
- APPENDIX ONE Glossary of Protein Domains
- APPENDIX TWO Inventory of Models, Mysteries, Devices, and Epiphanies
- APPENDIX THREE Genes That Can Alter Cell Fates Within the (5-Cell) Mechanosensory Bristle Organ
- APPENDIX FOUR Genes That Can Transform One Type of Bristle Into Another or Into a Different Type of Sense Organ
- APPENDIX FIVE Genes That Can Alter Bristle Number by Directly Affecting SOP Equivalence Groups or Inhibitory Fields
- APPENDIX SIX Signal Transduction Pathways: Hedgehog, Decapentaplegic, and Wingless
- APPENDIX SEVEN Commentaries on the Pithier Figures
- References
- Index
Summary
The A-P axis is governed by Hh and Dpp but not by Wg
Like the leg disc, the wing disc uses Hedgehog to set up a border zone just ahead of the A/P compartment boundary (cf. Fig. 5.7), but its zone emits only one long-range morphogen – namely, Dpp. Wingless is irrelevant for the wing's A-P axis and instead functions along its D-V axis. Both morphogens are essential: wings fail to develop when the disc is deprived of either Dpp or Wg.
Topologically, the wing is like a squashed leg (Fig. 6.1). Its D and V faces are apposed, and its veins run along its length like the leg's bristle rows. However, while the prospective bristle rows converge centrally in the leg disc (cf. Fig. 5.1), the primordia of veins 2–5 are parallel to one another and intersect a perpendicular line (the future margin). Thus, it is unclear whether the wing has a true “tip” like the leg. Certainly, the expression of Dll in a band along the wing margin (Fig. 6.2) differs from the circle of Dll in the leg disc (cf. Fig. 5.4).
The stripe where dpp is expressed in a mature disc is ∼5 cells wide.
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- Information
- Imaginal DiscsThe Genetic and Cellular Logic of Pattern Formation, pp. 137 - 196Publisher: Cambridge University PressPrint publication year: 2002