BIOL-UA 21 Lecture 22: Lecture 22
22 Dec 2016
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Lecture 22: post-transcriptional control: when the germ line is rst formed, transcription of all genes is repressed. All regulation is post- transcriptional; mrnas already exist: each step after transcription is a regulatory opportunity: Splicing during pre-mrna is a regulatory opportunity, and in different cell types, cleavage happens in different places, leading to alternative splicing. If you have different cleavage and polyadenylation sites, the 3" utr can be changed of a transcript and regulation happens there after transcription. Rna is unstable, and undergoes process of hydrolysis easily. If the rna spontaneously breaks in the middle, one. Rna has a cap, but no aaaa tail. The absence of a cap or tail is degraded. Rna editing: some mrna have their sequences changed. Rnas have to be transported through nuclear pores with the help of proteins. mrnas can then localize in the cytoplasm at speci c places and where they are localized is controlled (e. g. bicoid in drosophila).
