Wize AP Biology Textbook > Gene Expression & Regulation
Eukaryotic Post-Transcriptional Regulation
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Post-Transcriptional Regulation
RNA Alternative Splicing
In eukaryotes, after RNA has been transcribed, it must be processed before it is exported to the cytoplasm for translation into protein. One such processing is the removal of segments of RNA through splicing.
- Normally, introns are removed from RNA and exons remain to be expressed.
- It turns out that some exons can be removed to yield different proteins from the same RNA transcript. This is called alternative splicing.
- Therefore, this can be considered another level of gene expression control.
RNA Stability
RNA processing also includes the addition of a 5' cap and a poly-A tail to increase its stability and prevent it from degradation before it gets to be translated.
- RNA will inevitably still be degraded. If it degrades very quickly (unstable), little protein can be produced from it.
- RNA-binding proteins (RBPs) can bind to RNA (specifically, to the untranslated regions (UTRs)) to control stability.
- MicroRNAs (miRNAs) are short RNAs that can bind to protein-coding RNA to be block translation or tag it for destruction by the RNA-induced silencing complex (RISC).
- Short interfering RNAs (siRNAs) work similarly to miRNAs.
Practice: Alternative Splicing
Alternative splicing is...
Practice: Post-Transcriptional Regulation Mechanisms
Which of the following is true?