POST TRANSCRIPTIONAL EXPRESSION REGULATION, METHOD 3:mRNA LOCALIZATION
- Some mRNAs are localized at specific regions of the cytosol.
- These specific regions are localized by sequences in the 3’ UTR (untranslated regions before
the pol-A-tail.)
- Proteins bind these sequences and link the RNA to cytoskeleton
Untranslated regions known as 3’ UTRs are extensions of the stop codon that terminates protein
synthesis, they’re sequences when coupled have the potential to specify the way the RNA is to be used.
We know that mRNA carries information specifying the average lifetime and the protein they are
supposed to be translated into.
1.) To be localized, mRNA leaves the nucleus through nuclear pores
2.) The mRNA can be sent to their destination through 3 ways.
Some mRNA travel to their destination by associating with cytoskeletal
motors, which uses ATP. At their destination, mRNA is held in place by
anchor proteins.
Some mRNA are randomly diffused through the cytosol and trapped by
anchor proteins at localization sites.
Some mRNAs are degraded in the cytosol unless they have bound,
through random diffusion, a localized protein complex that anchors and
protects the mRNA from degradation.
Each mechanism requires specific signals on the mRNA, which are typically located at 3’UTR.
Here’s a more concrete example:
DROSOPHILA mRNA localization
Staufen is a gene required to localize maternal RNAs in the posterior pole of the Drosophila egg
and bicoid RNA at the anterior pole.
1.) bicoid 3’UTR has a sequence that is recognized by Staufen protein.
2.) Staufen links bicoid mRNA to microtubules at the anterior of the egg
3.) When translated, Bicoid protein diffuses from anterior.
POST TRANSCRIPTIONAL EXPRESSION REGULATION, METHOD 4: CHANGES IN mRNA STABILITY
- Some mRNAs are localized at specific regions of the cytosol.
- These specific regions are localized by sequences in the 3’ UTR (untranslated regions before
the pol-A-tail.)
- Proteins bind these sequences and link the RNA to cytoskeleton
Untranslated regions known as 3’ UTRs are extensions of the stop codon that terminates protein
synthesis, they’re sequences when coupled have the potential to specify the way the RNA is to be used.
We know that mRNA carries information specifying the average lifetime and the protein they are
supposed to be translated into.
1.) To be localized, mRNA leaves the nucleus through nuclear pores
2.) The mRNA can be sent to their destination through 3 ways.
Some mRNA travel to their destination by associating with cytoskeletal
motors, which uses ATP. At their destination, mRNA is held in place by
anchor proteins.
Some mRNA are randomly diffused through the cytosol and trapped by
anchor proteins at localization sites.
Some mRNAs are degraded in the cytosol unless they have bound,
through random diffusion, a localized protein complex that anchors and
protects the mRNA from degradation.
Each mechanism requires specific signals on the mRNA, which are typically located at 3’UTR.
Here’s a more concrete example:
DROSOPHILA mRNA localization
Staufen is a gene required to localize maternal RNAs in the posterior pole of the Drosophila egg
and bicoid RNA at the anterior pole.
1.) bicoid 3’UTR has a sequence that is recognized by Staufen protein.
2.) Staufen links bicoid mRNA to microtubules at the anterior of the egg
3.) When translated, Bicoid protein diffuses from anterior.
POST TRANSCRIPTIONAL EXPRESSION REGULATION, METHOD 4: CHANGES IN mRNA STABILITY
