Biology 3355A/B Study Guide - Final Guide: Fibrillarin, Heterochromatin, Purine
28 Jan 2018
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Original central dogma (1958: dna (gene) rna protein. Biogenesis of mature mirnas: transcribed by rna pol ii primary transcripts (pri-mirna) Only one strand recognized by argonuate and binds mirna. Examples of pre-mirnas: pre-mirnas transcriptis, stem-loop structures of 70 nt with imperfect base pairing in stem, discovered in nematode c. elegans encoded by non-protein coding genes lin4 and let7 (regulate embryogenesis and larval development) Types of mirna-target interactions: base pairing initiated by interactions of seed regions (2 -8 bp) of mirna at 3" of mrna. Gene targets of mirnas: 60% + of mammalian genes are targets, level 1 complexity: 1 mirna can control hundreds of different genes, level 2 complexity: 1 gene can be targeted by many mirna"s. 4 factors modulating functions of mirna during stress: level of mirna. Increase mirna = decreased expression of target: decrease mirna = increased expression of target. Exposed to hypoxia, expression of mirna increases (seen cells change colour: level of mrna targets target mimicry .
