Small RNAs and Silencing After Transcription
Short RNAs pair with a matching transcript and mark it for cutting or block its translation. A gene can therefore be fully transcribed and still produce almost no protein.
What a learner can do afterwards
- Explains how base pairing gives the silencing its specificity.
- Distinguishes cutting the transcript from blocking its translation by what happens to mRNA levels.
- Predicts what a measurement of mRNA alone would miss in a silenced cell.
1 · Read
Small RNAs silence genes after transcription by guiding a complex to matching transcripts. A microRNA loaded into Argonaute pairs with target messages, usually near the tail end, and the seed match picks exactly which transcripts get hit. Because pairing follows base rules, one small RNA can tune a whole set of targets that share its match.
The degree of pairing decides the outcome. A near perfect match slices the message and destroys it, so message levels fall. A partial match instead stalls the ribosomes and blocks translation while the message stays present, so message counts look normal while protein output drops.
Imagine a cell where messages measure normal but protein is nearly gone. An mRNA only assay reports nothing wrong and misses the regulation completely, because the block sits at translation. You must measure protein too: slicing shows in message levels, pure blocking shows only in protein.
When you judge silencing, first ask how well the guide pairs, then predict which readout moves: message, protein, or both.
Pairing picks the targets, and the fit decides whether the message dies or just goes unused.
2 · Watch
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Where it sits
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.