Cell-cell Communications in Development. Induction and Competence What do we mean by induction? How do we define define competence? competence?

Cell-cell Communications Cell-cell Communications in Developmentin Development

Induction and CompetenceInduction and Competence

What do we mean What do we mean by induction?by induction?

How do weHow do we definedefine competence?competence?

Where does Pax6Where does Pax6 fit in?fit in?

Induction and CompetenceInduction and Competence

Where can we observe reciprocal Where can we observe reciprocal inductions?inductions?

Induction and CompetenceInduction and Competence

What is the difference between What is the difference between instructive and permissive instructive and permissive interactions?interactions?

Epithelial-mesenchymal Epithelial-mesenchymal interactions interactions

How does this diagram illustrate the How does this diagram illustrate the regional specificity of induction?regional specificity of induction?

Epithelial-mesenchymal Epithelial-mesenchymal interactionsinteractions

How does this experiment illustrate the How does this experiment illustrate the genetic specificity of induction?genetic specificity of induction?

Paracrine Factors in DevelopmentParacrine Factors in Development

What is the connection between paracrine What is the connection between paracrine factors and induction?factors and induction?

Paracrine Factors in DevelopmentParacrine Factors in Development

How do fibroblast growth factors (FGF’s) How do fibroblast growth factors (FGF’s) induce changes in cells?induce changes in cells?

Paracrine Factors in DevelopmentParacrine Factors in Development

What is the Hedgehog family?What is the Hedgehog family?

Paracrine Factors in DevelopmentParacrine Factors in Development

The wnt family?The wnt family?

Paracrine Factors in DevelopmentParacrine Factors in Development

The TGF-The TGF-ββ superfamily?superfamily?

Signal Transduction PathwaysSignal Transduction Pathways

What is involved in signal What is involved in signal transduction?transduction?

Signal Transduction PathwaysSignal Transduction Pathways

How does the RTK pathway promote cell-How does the RTK pathway promote cell-cell induction?cell induction?

Signal Transduction PathwaysSignal Transduction Pathways

What are examples of some specific What are examples of some specific inductions that use the RTK pathway?inductions that use the RTK pathway?

Signal Transduction PathwaysSignal Transduction Pathways

How does the Smad pathway compare How does the Smad pathway compare with the RTK pathway?with the RTK pathway?

Signal Transduction PathwaysSignal Transduction Pathways

What pathway mediates both the What pathway mediates both the differentiation of blood cells and the differentiation of blood cells and the formation of milk for lactation?formation of milk for lactation?

Signal Transduction PathwaysSignal Transduction Pathways

How can the Wnt How can the Wnt pathway mediate pathway mediate cell division?cell division?

What are the What are the ramifications of ramifications of this pathway?this pathway?

Signal Transduction PathwaysSignal Transduction Pathways

How does the sonic hedgehog paracrine How does the sonic hedgehog paracrine factor influence limb and neural factor influence limb and neural development in vertebrates?development in vertebrates?

Signal Transduction PathwaysSignal Transduction Pathways

What happens in What happens in the absence of the absence of sonic hedgehog?sonic hedgehog?

How is cholesterol How is cholesterol involved here?involved here?

Cell Death PathwaysCell Death Pathways

What is the difference between What is the difference between apoptosis and necrosis?apoptosis and necrosis?

Why is apoptosis critical for Why is apoptosis critical for development?development?

What initiates apoptosis?What initiates apoptosis?

Cell Death PathwaysCell Death Pathways

What role has C. elegans played in our What role has C. elegans played in our knowledge of apoptosis?knowledge of apoptosis?

Juxtacrine SignalingJuxtacrine Signaling

How is this type of signaling different How is this type of signaling different from paracrine signaling?from paracrine signaling?

– signal molecule is a protein that resides signal molecule is a protein that resides in adjacent cell memberin adjacent cell member

Juxtacrine SignalingJuxtacrine Signaling

Juxtacrine SignalingJuxtacrine Signaling

Ligand resides in Ligand resides in extracellular matrix extracellular matrix of signaling cellof signaling cell

– fibronectinfibronectin– lamininlaminin

What kinds of What kinds of receptors are receptors are involved?involved?

Juxtacrine SignalingJuxtacrine Signaling

Gene activation by Gene activation by matrix attachmentmatrix attachment

Juxtacrine SignalingJuxtacrine Signaling

– signal transmitted signal transmitted from cytoplasm of from cytoplasm of one cell directly to one cell directly to cytoplasm of cytoplasm of second cellsecond cell

– use gap junctionuse gap junction

Pathway’s Cross TalkPathway’s Cross Talk

transcription may transcription may require activation require activation of two pathwaysof two pathways

one receptor can one receptor can activate different activate different pathwayspathways

Maintaining DifferentiationMaintaining Differentiation

Transcription factor as its own enhancerTranscription factor as its own enhancer

Maintaining DifferentiationMaintaining Differentiation

Prevent nucleosome formationPrevent nucleosome formation

Maintaining DifferentiationMaintaining Differentiation

Autocrine stimulationAutocrine stimulation

Maintaining DifferentiationMaintaining Differentiation

Paracrine loopParacrine loop