Drosophila Body plan Flashcards
Describe the role of bicoid gene in Drosophila development?
Anterior structures!
bicoid mRNA localised at anterior of newly laid egg
Gradient produced via bicoid protein movement and mRNA bicoid distribution
Describe the role of caudal protein in Drosophila
posterior gene!
mutations of this gene results in abnormal abdominal development
back to front gradient established by inhibtion of Caudal by Bicoid
What is the function of Nanos gene in drosophila?
Concentration gradient from posterior end.
Supresses maternal hunchback gene in the posterior end to prevent interference with embryos OWN hunchback genes, that are expressed from the anterior end.
THIS IS NANOS SOLE FUNCTION
Describe dorso ventral axis specification
Receptor is Toll protein
present throughout cell membrane of egg
How does the dorsal protein specify the drosal ventral axis
Gradient is formed with high point in most ventral middle region and with little or none in dorsal area.
After dorsal enters nuclei effects gene expression to divide dorso/ventrsl axis into well defined regions
what are gap genes and their function in drosophila
divide the A/P axis into five broad regions, expressed early in development
gap gene expression at different points along A/P axis controlled by concentration of bicoid and hunchback proteins, together with interactions between gap genes themselves.
define location of head
encode transcription factors which regulate the expression of the pair - rule genes
what are pair - rule genes?
expressed in alternating parasegments along A/P Axis later in the drosophila and define the edges of individual segments
How is the dorsal gradient establish ed?
After fertilisation spatzle ligand activates toll receptor to produce gradient of inter-nuclear dorsal protein along axis.
Spatzle processes preportein into active by binding to the toll receptor and toll signalling to dorsal transcription factor.
Signal translocates dorsal from cytoplasm to nucleus
