Overview
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R stands foreither adenine or guanine) is an optimal recognition sequence for translation initiation. The purine at -3 position and the guanine at +4 position are highly conserved throughout animal and plant species and regulate the initiation of protein synthesis. If the first start codon does not have a purine at -3 position and guanine at +4 position, then this sequence is in a weak context. For example, the peanut clump virus contains an RNA that encodes two proteins, p23 and p39. The first start codon is for p23 synthesis and has a weak recognition sequence, CUUAUGU. Around 30% of ribosomes will skip the first start codon and initiate translation at a downstream start codon instead, producing the second protein, p39. This initiation of translation at an alternative site is known as leaky scanning and has been observed in mRNAs of mammals, plants, and viruses.…
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Embed code vs URL
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What is an Embed Code?
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How to embed a video
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STEP 2: PASTE THE EMBED CODE INTO YOUR ENVIRONMENT
Embed codes can be used in most learning management systems (Canvas, Blackboard, Moodle…), organizational websites, and a host of other tools. The specifics of how to add in an embed code will depend on your environment.
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