Imaginal Discs: The Genetic and Cellular Logic of Pattern Formation

Note: Supplemental materials are not guaranteed with Rental or Used book purchases.

ISBN: 9780521584456 | 0521584450
Cover: Hardcover
Copyright: 5/13/2002

Rent

(Recommended)

$193.28

Term

Due

Price

Semester

Dec 12

$214.76

Quarter

Sep 3

$204.02

Short Term

Aug 13

$193.28

*This item is part of an exclusive publisher rental program and requires an additional convenience fee. This fee will be reflected in the shopping bag.
Buy New

Special Order: 1-2 Weeks

$274.94

Many of the 14,000 genes of Drosophila are involved in the development of imaginal discs. These hollow sacs of cells make adult structures during metamorphosis, and their study is crucial to comprehending how a larva becomes a fully-functioning fly. This book examines the genetic circuitry of the well-known 'fruit fly', tackling questions of cell assemblage and pattern formation, of the hows and the whys behind the development of the fly. After an initial examination of the proximity versus pedigree imperatives, the book delves into bristle pattern formation and disc development, with entire chapters devoted to the leg, wing, and eye. Extensive appendices include a glossary of protein domains, catalogues of well-studied genes, and an outline of signaling pathways. More than 30 wiring diagrams among over 60 detailed schematics clarify the text. No student or practising scientist engaged in the study of Drosophila genetics should be without this comprehensive reference.

Preface

Cell Lineage Vs. Intercellular Signaling

(4)

Discs are not clones

(3)

No part of a disc is a clone, except claws and tiny sense organs

(1)

Cells belong to lineage ``compartments''

(1)

The Bristle

(26)

Numb segregates asymmetrically and dictates bristle cell fates

(1)

Delta needs to activate Notch, but not as a signal per se

(5)

Amnesic cells can use sequential gating to simulate a binary code

(2)

Notch must go to the nucleus to function

(3)

E(spl)-C genes are Su(H) targets but play no role in the SOP lineage

(3)

The transcription factor Tramtrack implements some cell identities

(2)

Hairless titrates Su(H)

(3)

Several other genes help determine the 5 cell fates

(4)

Pox neuro and Cut specify bristle type

(1)

Bract cells are induced by bristle cells

(1)

Macrochaetes and microchaetes differ in size but not in kind

(2)

Bristle Patterns

(45)

Surprisingly, different macrochaete sites use different signals

(3)

Prepatterns may contain hidden ``singularities''

(1)

How Achaete and Scute control bristles was debated for decades

(7)

In 1989, Achaete and Scute were found to mark ``proneural clusters''

(1)

In 1995, the old AS-C paradigm toppled and a new one emerged

(1)

Proneural ``spots'' shrink to SOP ``dots''

(3)

The SOP uses a feedback loop to raise its Ac and Sc levels

(1)

Two other bHLH genes (asense and daughterless) assist SOPs

(1)

``Lateral'' or ``mutual'' inhibition ensures one SOP per PNC

(1)

Notch-pathway and proneural genes are functionally coupled

(2)

Doses of Notch-pathway genes can bias the SOP decision

(1)

Extra SOPs could be inhibited by contact or diffusion (or both)

(1)

Scabrous may be the diffusible SOP inhibitor

(2)

Inhibitory fields dictate the spacing intervals of microchaetes

(2)

Microchaetes come from proneural stripes, not spots

(4)

Hairy paints ``antineural'' stripes on the legs

(1)

Leg bristles use extra fine-tuning tricks

(5)

Chemosensory leg bristles are patterned like notal macrochaetes

(1)

Extramacrochaetae superimposes an uneven antineural ``mask''

(3)

Dose dependency implies that HLH proteins ``compute'' bristles

(2)

Robustness of patterning may be due to a tolerant time window

(1)

Atonal and Amos are proneural agents for other types of sensilla

(1)

Other (upstream) pathways govern bristle patterning

(1)

Origin and Growth of Discs

(21)

Segmentation genes set the stage for disc initiation

(4)

Prepatterns and gradients clashed in trying to explain homeosis

(4)

Homeotic genes implement regional identities

(1)

Wing and haltere discs ``grow out'' from 2nd- and 3rd-leg discs

(2)

Thoracic discs arise at Wingless/Engrailed boundaries

(4)

Cell lineage within compartments is indeterminate

(1)

The Polar Coordinate Model linked regeneration to development

(4)

But regeneration has peculiarities that set it apart

(1)

The Leg Disc

(40)

The Molecular Epoch of disc research was launched in 1991

(2)

Bateson's Rule (1894) governs symmetry planes in branched legs

(1)

Meinhardt's Boundary Model deftly explained Bateson's Rule

100

(3)

The Boundary and PC Models jousted in a ``Paradigm War''

103

(2)

Hh, Dpp, and Wg are the chief intercellular signaling molecules

105

(2)

P-type cells use Hh to ``talk'' to A-type cells nearby

107

(2)

Hh elicits expression of Dpp and Wg along the A/P boundary

109

(2)

Dpp dorsalizes and Wg ventralizes, or do they?

111

(3)

Dpp and Wg are mutually antagonistic

114

(1)

Dpp and Wg jointly initiate distal outgrowth

115

(3)

But Dpp seems more crucial than Wg as a growth factor

118

(1)

The A/P boundary can migrate when its ``jailors'' are ``asleep''

119

(3)

Regeneration is due to a Hh spot in the peripodial membrane

122

(1)

The Polar Coordinate Model died in 1999

123

(1)

How Hh, Dpp, and Wg move is not known, nor is their range

124

(1)

Whether Dpp and Wg travel along curved paths is not known

125

(3)

Hairy links global to local patterning

128

(1)

Questions remain about the Hh-Dpp-Wg circuitry

128

(1)

Distal-less is necessary and sufficient for distalization

129

(3)

Proximal and distal cells have different affinities

132

(1)

Dachshund is induced at the Homothorax/Distal-less interface

132

(1)

Homothorax and Extradenticle govern the proximal disc region

133

(1)

Fasciclin II is induced at the BarHl/Aristaless interface

134

(1)

BarHl and Bric a brac affect P-D identity, joints, and folds

135

(1)

Leg segmentation requires Notch signaling

135

(2)

The Wing Disc

137

(60)

The A-P axis is governed by Hh and Dpp but not by Wg

137

(3)

Dpp turns on omb and spalt at different thresholds

140

(3)

Dpp regulates omb and spalt similarly despite clues to the contrary

143

(1)

Dpp does not regulate tkv in 3rd instar despite clues to the contrary

143

(5)

A vs. P identities might explain haw a straight A/P line emerges

148

(1)

But the A/P line appears to straighten via a signaling mechanism

149

(4)

Intercalation is due to a tendency of Dpp gradients to rise

153

(2)

The variable height of Dpp gradients makes them appear seamless

155

(1)

A Wg gradient specifies cell fates along the wing's D-V axis

156

(1)

Perpendicular (Dpp x Wg) gradients suggest Cartesian coordinates

157

(1)

But cells do not seem to record positional values per se

158

(1)

Wg's repression of Dfz2 is inconsequential

158

(1)

Apterous's role along the D-V axis resembles Engrailed's A-P role

158

(2)

Chip cooperates with Apterous, and ``Dorsal wing'' acts downstream

160

(1)

Serrate and Delta prod Notch to evoke Wg at the D/V line

161

(3)

Fringe prevents Notch from responding to Serrate

164

(1)

The core D-V circuit plugs into a complex network

165

(2)

The wing-notum duality is established by Wg and Vein

167

(4)

But Vestigial and Scalloped dictate ``wingness'' per se

171

(2)

Straightening of the D/V border requires Notch signaling and Ap

173

(1)

Straightening of veins may rely on similar tricks

173

(1)

Two cell types predominate in the wing blade: vein and intervein

174

(1)

Veins come from proveins that look like proneural fields

175

(1)

But the resemblance is only superficial

175

(2)

All veins use the EGFR pathway

177

(7)

But interveins also use the EGFR pathway (at a later time)

184

(1)

Veins 3 and 4 are positioned by the Hh pathway

185

(1)

Veins 2 and 5 are positioned by the Dpp pathway

186

(2)

The Dpp pathway later implements the vein state

188

(1)

A cousin of Dpp (Gbb) fosters the A and P cross-veins

188

(1)

Vein 1 uses a combination of Dpp and Wg signals

189

(1)

Macrochaetes are sited by various ``prepattern'' inputs

190

(1)

Haw bristle axons get wired into the CNS is not known

191

(6)

The Eye Disc

197

(40)

Compound eyes have ~ 750 facets, with 8 photoreceptors per facet

197

(4)

Unlike the bristle, the ommatidium is not a clone

201

(1)

The eye has D and V compartments (despite doubts to the contrary)

202

(1)

The Iroquois Complex controls D-V polarity via Fringe and Notch

203

(5)

A morphogenetic wave creates the ommatidial lattice

208

(1)

D-V polarity depends on a rivalry between R3 and R4 precursors

209

(2)

R1-R8 cells arise sequentially, implying a cascade of inductions

211

(2)

But the final cell (R7) is induced by the first one (R8)

213

(1)

Various restraints prevent more than one cell from becoming R7

213

(3)

The information content of the inductive signals may be only 1 bit

216

(2)

No transcription factor ``code'' has yet been found for R cells

218

(6)

The lattice is created by inhibitory fields around R8 precursors

224

(3)

The lattice is tightened when excess cells die

227

(1)

Eye bristles arise independently of ommatidia

228

(1)

The MF operates like a moving A/P boundary

229

(5)

Dpp and Wg control the rate of MF progress

234

(1)

The MF originates via different circuitry

234

(3)

Homeosis

237

(19)

BX-C and ANT-C specify gross metameric identities along the body

237

(6)

Ubx enables T3 discs to develop differently from T2 discs

243

(1)

But Ubx does so by directly managing target genes in multiple echelons

244

(3)

Pc-G and Trx-G ``memory'' proteins keep homeotic genes on or off

247

(2)

Homothorax, Distal-less, and Spineless specify leg vs. antennal fates

249

(3)

If a ``master gene'' exists for the eye, then it is also a micromanager

252

(2)

The manifold ``enhanceosome'' is a wondrous Gordian Knot

254

(1)

The deepest enigma is how evolution rewired the circuit elements

254

(2)

Epilogue

256

(1)

Appendix One. Glossary of Protein Domains

257

(9)

Appendix Two. Inventory Of Models, Mysteries, Devices, And Epiphanies

266

(5)

Appendix Three. Genes That Can Alter Cell Fates Within The (5-Cell) Mechanosensory Bristle Organ

271

(5)

Appendix Four. Genes That Can Transform One Type Of Bristle Into Another or Into a Different Type of Sense organ

276

(2)

Appendix Five. Genes That Can Alter Bristle Number by Directly Affecting SOP Equivalence Groups or Inhibitory Fields

278

(7)

Appendix Six. Signal Transduction Pathways: Hedgehog, Decapentaplegic, and Wingless

285

(12)

Appendix Seven. Commentaries On The Pithier Figures

297

(10)

References

307

(134)

Index

441

Please wait while the item is added to your bag...

FREE SHIPPING

Rent More, Save More! Use code: BBRENTAL

5% off 1 book, 7% off 2 books, 10% off 3+ books

Imaginal Discs: The Genetic and Cellular Logic of Pattern Formation

Summary

Table of Contents

Supplemental Materials

FREE SHIPPING

Rent More, Save More! Use code: BBRENTAL

5% off 1 book, 7% off 2 books, 10% off 3+ books

Imaginal Discs: The Genetic and Cellular Logic of Pattern Formation

Summary

Table of Contents

Supplemental Materials

Digital License