Cellcell Communications in Development Induction and Competence u

Cell-cell Communications in Development

Induction and Competence u u u What do we mean by induction? How do we define competence? Where does Pax 6 fit in?

Induction and Competence u Where can we observe reciprocal inductions?

Induction and Competence u What is the difference between instructive and permissive interactions?

Epithelial-mesenchymal interactions u How does this diagram illustrate the regional specificity of induction?

Epithelial-mesenchymal interactions u How does this experiment illustrate the genetic specificity of induction?

Paracrine Factors in Development u What is the connection between paracrine factors and induction?

Paracrine Factors in Development u How do fibroblast growth factors (FGF’s) induce changes in cells?

Paracrine Factors in Development u What is the Hedgehog family?

Paracrine Factors in Development u The wnt family?

Paracrine Factors in Development u The TGF-β superfamily?

Signal Transduction Pathways u What is involved in signal transduction?

Signal Transduction Pathways u How does the RTK pathway promote cell induction?

Signal Transduction Pathways u What are examples of some specific inductions that use the RTK pathway?

Signal Transduction Pathways u How does the Smad pathway compare with the RTK pathway?

Signal Transduction Pathways u What pathway mediates both the differentiation of blood cells and the formation of milk for lactation?

Signal Transduction Pathways u u How can the Wnt pathway mediate cell division? What are the ramifications of this pathway?

Signal Transduction Pathways u How does the sonic hedgehog paracrine factor influence limb and neural development in vertebrates?

Signal Transduction Pathways u u What happens in the absence of sonic hedgehog? How is cholesterol involved here?

Cell Death Pathways u What is the difference between apoptosis and necrosis? u Why is apoptosis critical for development? u What initiates apoptosis?

Cell Death Pathways u What role has C. elegans played in our knowledge of apoptosis?

Juxtacrine Signaling u How is this type of signaling different from paracrine signaling? – signal molecule is a protein that resides in adjacent cell member

Juxtacrine Signaling

Juxtacrine Signaling u Ligand resides in extracellular matrix of signaling cell – fibronectin – laminin u What kinds of receptors are involved?

Juxtacrine Signaling u Gene activation by matrix attachment

Juxtacrine Signaling – signal transmitted from cytoplasm of one cell directly to cytoplasm of second cell – use gap junction

Pathway’s Cross Talk u u transcription may require activation of two pathways one receptor can activate different pathways

Maintaining Differentiation u Transcription factor as its own enhancer

Maintaining Differentiation u Prevent nucleosome formation

Maintaining Differentiation u Autocrine stimulation

Maintaining Differentiation u Paracrine loop