What is developmental biology Why we need to understand ......development –>> underlying mechanism is different from that of artificial manufacturing –>> we need to know the mechanism

introduction of developmental biology

• What is developmental biology

• Why we need to understand the mechanism of animal development

• Why developmental biology is so interesting

Developmental of frog

Development of sea urchin

Development of chick

Structure = function

• Aim of Developmental Biology is to find how animal structures are formed

• So, we need to know how the structure and the function is related.

• Examples

– Ossicles(耳小骨）

– Inner ear（内耳）

– others

Knowing the mechanism of plant structures,,,

• Simple rule

– bifurcation

Parameters: length of each part, angle of bifurcation, frequency of bifurcation

Tree generator

Plants in the CG movies

Knowing the mechanism of skin pattern formation,,,

C:/Users/skondo/Desktop/movie/その他のmovie/発生の動画/Zebrafish egg development over 24 hours.flvC:/Users/skondo/Desktop/movie/その他のmovie/発生の動画/Zebrafish egg development over 24 hours.flv

Is the principle of the development very complex ?

• It could be. But cells can do it.

• >>it may be simple.

• In case of sea shells,,,,,

Shells grow only at the edge

How to make coiling sea shells

How to make the Bivalvia

Shells grow only at the edge

By changing the shape of this growing ring >>> many different sea shells are made.

Developmental biology

Fertilized egg (mouse)Correctly arranged in space(by Hamada)

Differentiation( by Oda)

Morphogenesis(by Kondo)

Two questions

• 1) explain how the Kon-Pei-Tou is made

作業工程

• Keep rolling the heated giant pan• Spread the water containing high concentration of

sugar• Keep above operations for three days

何が起きる？

転がる

砂糖のつぶ（半分液状）

どこにくっつく？？

砂糖のつぶ（半分液状）

どこにくっつく？？

Swelling part swells more

A hollow(dent) does not swell because it does not touch the pan

Growth of coral

Corals eat planktons

Two questions

• 2) explain how the shell of a turtle grows

problem

• Shell can not be added from outside because no living cells is there.

shell

Cells making the shell

Developmental biologyBiological process in which a fertilized cell forms a

complex structure of adult body

Inside of a sperm ? (1700~)

Simply expand ?

Developmental biologyBiological process in which a fertilized cell forms a

complex structure of adult body

Dynamically changes the shape.From simple to complex.

What is the underlying mechanism? Why we need to know it ?

Structure = Function

Structure = Function

Dialyzer for kidney disease patients

In order to take care or cure these tissues, we need to how it is made.

Difference between man-made machines and animals

Need to be assembled by some other autonomous

autonomy

Difference between man-made machines and animals

regeneration

Need to be taken care Regenerates autonomously

Developmental biology

• What is developmental biology– >> to understand how the complex structure is made

• Why we need to study the mechanism of development– >> underlying mechanism is different from that of

artificial manufacturing– >> we need to know the mechanism to cure the

diseases– >>FUN!!

Strange structures

Sea dragon thorny oyster basket star

Pikachu sea snailTreehopperSp. of land snail

Megaloceros giganteus

Unicorn whale

Shapes of real animals are sometimes much odder than monsters in the film

Stalk-eyed flies

Sp. of Treehopper

Rarely not in the shape of living things, , ,

Sp. of sponge Sp. of sea cucumber

Question What kind of mechanism can

generate all these structure ??

How is the structure complex ?Tissue levelOrgan, whole body

gene networkCell-cell interactionPhysical stress

Ligand-receptorCell migrationPolarity

Cell level

Shigeru KondoToday

Hiroshi Hamada6/1

Tohru nakano6/1

Origin of Shape

No structure uniformsymmetric

structuredifferenceasymmetric

Principles to form structuresKey wards of development

1. Physical constraint

2. Pattern in the egg

3. Epithelization1. Basal-apical polarity

2. Folding of cell sheet

4. Planer cell polarity

5. Compartment1. Master controller gene

6. Wave (Turing wave, BZ wave)

7. Apposition growth1. Sea shell

2. DLA

8. Fractal

Earlymicro

Late macro

Physical constraint

compaction

Cadherin binds the cell membranes

Compaction inducesCell polarity and Differentiation

Origin of embryo

Origin of placenta

Cell polarity

Positional information in eggs

Bicoid gene

Difference is already set in an egg!!

Positional information in eggs

High conc. >>Head

Middle conc.>>Thorax

Low conc.>>Abdomen

Key wordsSegmentation genesGradient modelMorphogen

Cascade of gene induction make the pattern more complex

Gene networkSegmentation genes in drosophila

From assembled cells to a bag of cell sheet

Sea urchin vertebrates

Shapes are made by the folding of cell sheet

Apical contraction Change of cell shape induce the folding of cell sheet

filopodiaWhat is the source of force ?

Shapes made by the folding of cell sheet

Nerve tube (vertebrates) Eye development

Shapes made by the folding of cell sheet

Drosophila ventral furrow

Frog gastrulation

Planar cell polarityCell sheet needs to the direction to grow

PCP mutants

Drosophila wing Mouse hair Drosophila eyeMouse sound sensory hair

How to decide the directionality


Black are accumulated here

Black-yellow binds with high affinity

Passively yellow accumulated


Black-yellow binds with high affinity

Blacks come to bind yellowPassively yellow accumulated

Compartment

Large structures are built by assembling the parts.

Is the body of animal continuous?Or can be divided into parts?

Too large structure is difficult to built correctly.

Expression of genes show discreet boundaries

Posterior half

Anterior half

Expression of engrailed gene

Cells exclude each other

Patterns are made during development

Pattern identified by gene expression

Drosophila embryo

Patterns in zebrafish brain

Pattern identified by gene expression

The adult mouse cerebellum is subdivided into an

array of >100 reproducible stripes

Gene expression in a compartment

Down stream genes Down stream genes

Master controller

Master controller gene of eye formation =pax6

Ectopic expression of pax6

Ectopic leg formation by antenapedia gene

Ectopic head formation of hydraby wnt gene

Mutations in flower

Sepal: 萼(がく)片 Petal：花弁 stamen: 雄蕊 carpel:心皮（めしべ）

Se pe pe se se ca se st st pe

waves

• Turing equation

stable wave Travelling wave

Example of Turing wave

Does Turing mechanism involve in other system?

Cellular slime mold

In all process of development the travelling wave exists

Wave is made by the cAMP signal

Receive the

cAMP signal

Deliver cAMP

Cells move toward the direction

of cAMP signal coming

Relay of cAMP signal

Migration of cells induced by cAMP

cAMP release

migration

Freezing for a while

cAMP

What does happen with wave and migration ?

Center of spiral

Center of spiral is stable !

Falling down by gravityand move

simulation

Cells rolling in the slime

Fractal structure< repeated simple deformation

Tree generator

Plants in the CG movies

レポート課題

• 伸び縮するシートを使って、この形（ﾖﾂｺﾌﾞﾂﾉｾﾞﾐ）どうやって作るかを考える

Documents

What is developmental biology Why we need to understand ......development –>> underlying mechanism is different from that of artificial manufacturing –>> we need to know the mechanism