pastor lecture 3 Flashcards
What is the path for ERV/LTR retrotransposon?
-transcription–>mRNA–>reverse transcription–>dsDNa–>integration into DNA
What is pathway for non-LTR retrotransposon?
WHat about for DNA transposons?
-transcription–>mRNA—>target primed reverse transcription–goes in DNa
-excision–>dsDNA–>integration into gene
what can transposon insertion into middle of gene cause?
What can you sequence gene with?
-it can cause damage or mutation
-can sequence with PCr to see where the mutagenic transposon is in, for genetic screens, to see what gene/enhancer you disrupted
What are the 3 things a modified P element can do?
nsertional mutagenesis: p-element lands in gene, disrupts its function
* “Gene trap”: same as above, with reporter that is expressed with gene
* “Enhancer trap”: p-element lands near enhancer, contains reporter that is expressed when enhancer is active
What is the clevage stage between?
What is ZGA, what degrades?
it is between the 2 to 16-cell stage when the cells are getting smaller
-zygotic genome activation, when this occurs transcription starts occiring from embryo and mother DNA starts to degrade
What happens at 16 cell stage?
What fill up and forms?
What is ZGA between in development?
-you can see divergence since there is a distinct inner and outer cell, embryo fills up with fluid and forms a blastocyst
-between the 2-4 cell stage in mice and the 8-16 cell stage in humans
What do inner cells of blastocyst become?
-they become the epiblast, and the blastocyst burrow into endometrial wall
What does the primitive endoderm form?
What does pregnancy test, test for?
forms early structures like yolk sack but it is not involved in later development
-tests for HGC levels that come from placenta
When does placenta emerge?
What does it mediate, create and dampen?
-emerges after birth
-mediates nurients+gas exchange from mother
-placenta makes physical conact with mothers blood
-it also creates hormones and the placenta dampens mothers immune response
What is the primitive streak?
groove is in disk where cell differentiation is occuring and where gastrulation occurs
What is gastrulation?
What is the epiblast?
-where differentiation occurs
epiblast is pluripotent until gastrulation occurs
what does the ectoderm, mesoderm, and endoderm form?
what happens to cells as a result of differentiation?
ectoderm=neuronal cells
mesoderm=muscle cells
endoderm=digestive cells
-they become motile
Where do migrating cells move?
where does the endoderm form
-they move inward
-form bottom layer of embryo
Where does the primitve streak start?
What does gastrulation develop in the body?
-starts in the posterior end
-it helps develop the body axis, the postrior and he anterior axis
What happens after gastrulation?
At the 17 day mark?
-cells take on a specialized function and organs start to form
-day 17=notochord starts to form which helps guide development to help signaling
What happens at At the 19 day mark of embyronic development?
at the 20 day mark?
19 day mark=neural groove will form neural tube
20 day mark=gives rise to the neyral fold and somites (gives rise to muscles, cartilage and CT)
Where are hox genes expressed?
When are they activated?
-expressed along anterior-posterior axis
activated during gastrulation which is important for forming anterior and posterior axis
How many hox genes do humans and mice have?
What axis is developed earlier?
-humans and mice have 4 clusters of Hox genes
-anterior typically developed earlier
What happens when morphogen gradient forms?
-cells closest to morphogen get more signaling and there are different levels of morphogen causing different cells to form+
What secreted BMP morphogen proteins?
What does the floorplate and notochord secrete?
-roofplate and adjacent cells secrete BMP (dorsal end)
-they secrete soni hedgehog protein (ventral end)
What does BMP do in the pathway?
-BMP phosphorylates Smad and goes onto mediate transcription
