Ch. 3 pt 2 Flashcards
An example of alternative RNA splicing for tumors is _______, which makes a big difference in protein function
Bcl-x
What is the difference between Bcl-XL and Bcl-XS?
Bcl-XL inhibits apoptosis
Bcl-XS promotes apoptosis
drosophila gene _______ contains 24 exons with multiple splice site possibilities
dscam1
- differential splicing allows neurons to have unique identity
A single base-pair change at the 5’-end of exon 2 in the human _______ gene prevents splicing and generates nonfunctional mRNA
beta-globin
Mutation in ______ gene causes severe and life-threatening anemia
beta-globin
a mutation in the _______ gene causes skipping an intron and leads to a form of muscular dystrophy
dystrophin
mutations in the _______ gene have produced family members with extreme muscle formation
myostatin
The longer an mRNA persists in the cytoplasm, the more it can be translated. This depends largely on what?
the length of its poly-A tail
- can also be affected by proteins
_______ is an example of a protein that can increase the half-life of casein mRNA during lactation
prolactin
prolactin is an example of a protein that can increase the half-life of _______ during lactation
casein mRNA
_______ typically produce and store large quantities of mRNA’s in a dormant state. When are they translated?
Oocytes (unfertilized eggs)
- arent translated till after fertilization
In oocytes, mRNA regulation is _______, preventing translation until a proper signal is received
negative
In amphibians, _______ protein binds to the 5’ cap and 3’ poly-A tail creating a configuration that prevents translation
maskin
Explain the 2 steps maskin takes to prevent translation of an mRNA
1) maskin binds to CPEB, which attaches to 3’UTR
2) maskin binds to eIF4E factor attached to 5’cap
What does CPEB stand for?
cytoplasmic polyadenylation element-binding protein
Explain the 5 steps to initiate a maskin dormant mRNA
1) progesterone activates kinase that phosphorylates CPEB
2) CPEB binds to CPSF
3) CPSF stimulates poly-A-pol
4) PABP binds to the extended tail
5) stablizes interaction between eIF4E and eIF4G (ribosome assembly)
It has long been assumed that ribosomes do not show favoritism for some mRNAs. This is NOT reality. What is an example?
Rpl38 ribosome that translates HOX genes
_______ are short antisense RNA molecules that are complimentary to small regions of other mRNA’s
miRNA’s
What is an example of miRNA’s in C.elegans?
lin-4 miRNA binding to lin-14 RNA inhibiting synthesis of LIN-14
_______: the process by which miRNAs inhibit expression of specific genes by degrading or binding to their mRNA’s
RNA interference
What is the process of RNA interference?
1) miRNA ds loops are processed by Drosha and Dicer to make ss miRNA
2) ss miRNA are packaged into RNA-inducing silencing complexes (RISC)
3) silencing, aided by argonaute, occurs
1) miRNA ds loops are processed by _______ and _______ to make ss miRNA
2) ss miRNA are packaged into _______
3) silencing, aided by _______ occurs
1) Drosha, Dicer
2) RNA-induced silencer complexes
3) argonaute
_______ family proteins are particularly important to the activity of RISC
argonaute
What are the 2 major outcomes of RNA interference?
1) translational repression
2) mRNA destruction
by physically moving mRNA’s around not only can the timing of translation be controlled, but the _______ can also be specified
location
What are the 3 different mechanisms for moving mRNA around the cell?
1) diffusion and anchoring
2) localized protection
3) active transport along the cytoskeleton using microtubules
The mechanisms for moving mRNA are most often accomplished through interactions with their _______
3’-UTR’s
ATPase motor proteins:
- _______ (- ends of microtubules)
- _______ (+ ends of microtubules)
dynein
kinesin
What is a zymogen?
inactive enzyme (needs further processing)
make sure to review tools for developmental biologists:
mRNA, proteins, and protein function
STUDY
- SNOW DROP
(33:10 in ch3 pt2)
