key concept 16.5 Eukaryotic Gene Expression Can Be Regulated after Transcription

Eukaryotic gene expression can be regulated both in the nucleus prior to mRNA export, and after the mRNA leaves the nucleus. This can happen in several ways.

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  • Alternative splicing can give rise to multiple mRNA molecules from a single primary mRNA transcript.

  • MicroRNAs (miRNAs) are short single-stranded RNA molecules complementary to mRNAs that bind to and inhibit mRNAs from being translated.

  • Small interfering RNAs (siRNAs) perform a similar role in the cell as miRNAs but have a viral origin.

  • Single-stranded RNA can form secondary structures that inhibit its translation.

  • The cell tags proteins to be degraded with ubiquitin, which leads to its binding to a proteasome, where degradation occurs.