Lecture 37 Flashcards
Summarize using p element
inverted repeats flank transposase
Reporter gene = lacz, gfp
selection gene, eg w+, also changes fly eye colour to red
inject into germ cells and integrates
some have inetgrated transopases = sign = red eyes = …look for transgenic flies with a specific phenotype
describe gene trap - detailed
interrupts gene causes lof
inserts a reporter that can be used to visualize where gene expressed
usually combined with a genetic screen to provide additional info
enhancer regulate expression, inserted and spliced in to gene, fusion protein, shows where its expressed
describe enhancer trap - detailed
used to identify enhancers that promote gene expression in a specific cell type
inserted dna does not need to land inside a gene (has its own promoter)
own promotyer = can land wherever just not inside gene, enhancer turns on = enhance activity, coloured now
how does a single become an organized and functional organism
3 basic concepts =
cell proliferation
cell differentiation = one cell to diff types
cell morphogenesis = move around and makes shapes
all 3 happen at same time
describe first days of mammalian development
fetilize then grows, major ega, compaction, cavitation, cells can become anything, early blastocyst (inner cell mass and cavity), trophectoderm = from inner cell mass–>epiblast and primitive endoderm, not totipotent, late blastocyte, expansion and hatching, implantation = now = implantation and development = limit for in vitro culture
ega = maternal degrades and then starts zygotic - zygotic or embryonic genome activation, e1.5 mouse and e4.0, humans
compaction = increae adhesion
Cavitation = blastocel formation, helps so h2o wont leak and pumps h2o in
what guides early differentiation
cell position
describe cell contact and growth - specific ex
trophectoderm becomes placenta, inner cell mass becomes humans
no cell contact = one layer just facing fluid and not cell
- f actin accumulates, exposed outer membrane, binds kinases so wont phosphorylate = turns on genes for trophectoderm differentiation
cell cell contact = surrounded
- inside cell, lats1/2 –> yap wwtr, lats phosphorylated by kinase so doesnt go into nucleus, doesnt turn on genes for trophectoderm differentiation
activates changes in hippo signalling pathway
what does epiblast udergo
Gastrulation
can make any cell in body
restricts cell potency
describe parts of gastrulating epiblast
primitive streak = site of gastrulation
Ectoderm
mesoderm - down further migrating cells - migrate down
makes endoderm
what does gastrulation generate
3 embryonic germ layers
name and describe 3 embryonic germ layers
ectoderm = outer layer, cns, neural crest
mesoderm = middle layer, dorsal, head, lateral, paraxial, intermediate, muscle, blood, bones
endoderm - internal layer, gut and lungs, digestive tube, pharynx, respiratory tube
what does gastrulation also establish and describe
3 main body axes
anterior posterior
ventral dorsal
right left
right organs in right spots
head and brain = anterior, form, no streak
primitive streak = towards posterior end
dorsal = top, ventral = down below endoderm
once have layers = organogenesis, makes organs, in right place
what is anterior posterior patterning controlled by and describe
Genetically controlled
Forward genetic screen
Mutation of ultrabithorax (ubx) casues a homeotic transformation = loss of ubx - misisng haltere, but double wing, gain of ubx = opp
ubx expressed in specific region - makes halteres here, so fluorescnce in sit hybridization = reocgnize mrna
what do hox genes control and describe
anterior posterior patterning
drifted loss
transcription factors important for patterning
Conserved between animals
each expressed in specific places
what do mice use
Mice use the same genetic strategy to pattern the A-P axis
