BIO230H1 Lecture Notes - Lecture 7: Antisense Rna, Lysine, Transfer Rna
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BIO230H1 Full Course Notes
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Document Summary
Both prokaryotes and eukaryotes use translational control mechanisms to regulate protein expression often in response to stressful situations such as low nutrients, infection or environmental stress (e. g. temperatures) Prokaryotes: mrna have a 6 nucleotide shine dalgarno (sd) sequence. Correctly positions aug in the ribosome and provides translational control mechanisms: mechanism 1: rna binding protein blocks access to sd sequence. Ribosome is not correctly positioned no protein is made: mechanism 2: temperature regulated rna structures (e. g. virulence genes of human pathogen listeria monocytogenes) At lower temperatures: stem loop rna structure blocks sd due to lots of base pairing. As you increase the temperature to 37 degrees: you break the hydrogen bonds in stem loop region exposing the sd sequence: mechanism 3: riboswitch (e. g. s-adenosyl methionine) Small molecule causes structural rearrangement of rna blocking sd: mechanism 4: antisense rna (e. g. iron storage proteins) Antisense rna, produced somewhere else in the genome, base pairs with mrna and blocks sd.
