Lecture 13 - Control of Gene Expression (CH 8) Flashcards
What happens once the trp operon is removed in E coli? This means that …
The cell and its babies wont remember that; future cells won’t maintain their on or off state (that was done by a trp operon)
What’s different or the same between e coli and human (or other multicell) organisms regarding operons?
We have to maintain the on or off state
The maintainance of gene expression and transcription regulation is called
cell memory
What is it called when groups of transcriptional regulators work together to express one gene?
It is called combinatory control
How do we determine if a gene is on or off?
Signal integration
Seven stripes along the fly embryo correspond to what along thw fly? And what gene creates this?
7-14 segments; Even skipped (Eve) gene
How can we find how a gene (i.e. Eve) shows or does not show? Where do they get placed
Reporter Genes! Behind an upstream sequence
Give 2 examples of reporter genes
They tell us what to look for (i.e. lac z finds color and fluorenscents do filters)
Eve can expand transcription if either of which repressors are gone in stripe 2?
giant and krupel
What two activators need to be there for eve to expand transcription?
bicoid and hunchback
Presence of cortisol in the ___ activates ___ protein
Liver; cortisol receptor protein
Undifferentiated stem cells are in which state
Pluripotency
How many genes can be controlled by 1000 transcriptional regulators?
24,000 human genes
What does Ey regulate?if you put that gene in the wrong spot, what would happen?
The growth of an eye on fly. ectopic structures can form (i.e eye on a leg)
Give an example of reprogramming cells
You can reprogram a liver to a neuronal cell
Reprogramming cells uses de differentiating that creates ___ cells in order to remake them
Induced pluripotent cells (iPS)
How can we maintain cell memory
We can use positive feedback loops to keep transcription keep going on
How do cells maintain DNA methylation?
An enzyme called maintainance methyltransferase continues to inherit methylation after cell division happens. It does this by methylating the sites opposite the template strand.
Where does DNA methylation happen on a strand of DNA?
Methylation happens on CYTOSINE bases in 5 prime C G to 3 prime combinations
Cell memory mechanisms are forms of ___. Give three examples of how its done!
Epigenetic inheritance; methylation, histone modification, and positive feedback loops
How is listeria able to infect cells?
It is a thermosensor that detects 98 degrees on the hairpin mRNA structure in order to infect.
How do mRNA sequences control their translation?
RNA binding proteins can stop specific mRNAs from translating. i.e they stop ribosomes from binding to their site in mRNA
What is the job of miRNAs? What are they processed by?
microRNAs target mRNAs and destroy them mwahhahahaha; Dicer protein
miRNA becomes part of a ____.; what happens?
RNA induced silencing complex (RISC); the complex searches for mRNA match to kill and that mRNA cant make protein
