Morphogens, Induction and Competence Flashcards
What are the three types of intracellular signalling?
- Diffusion of signals –> membrane-bound receptors
- Membrane-bound receptor –> complementary membrane-bound receptor
- Diffusion of signals –> intracellular receptors
What is a morphogen?
A signalling molecule produced from a localised source and spread away to form a concentration gradient
What does cell fate depend on with morphogens?
Cell fate depends on the [morphogen] –> gradient determine pattern of development
What model is used to describe basic pattern formation?
The French flag model
What is induction?
Signalling from one cell type to another, with a change in specification of the responding cell
What is competence?
The ability to respond to a signal
What is an example of a morphogen?
Bicoid in Drosophila
In bicoid mutant eggs, what structure is lacking?
Head structures
Where is bicoid mRNA localised?
To the anterior end
How is the bicoid gradient formed?
By diffusing through the cytoplasm of the syncytial blastoderm
What does bicoid do?
Enters nuclei to regulate the expression of the hunchback gene which codes for a transcription factor involved in embryo segmentation
Which gene is associated with bicoid?
Hunchback
What is the hunchback gene in Drosophila involved in?
Embryo segmentation
What kind of gene is hunchback?
A gap gene - Genes involved in the development of segmented embryos