GeneRegulation160-page13 - In humans, translation of the...

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Gene Regulation - 13 mRNA Processing Gene Regulation When mRNA is processed, we can get different functional mRNA transcripts depending on which part of the primary transcript is determined to be introns and which exons. These differences can be accomplished via alternative splicing by the spliceosomes, thereby controlling gene activity, examples of which were discussed earlier. Post Transcription Controls of Gene Activity Duration of the mRNA Transcript The length of time a mRNA transcript can be read prior to degradation will affect the amount of final product, which will affect cell activity. Some mRNA lasts for weeks; some for hours. Translation Control Blocking mRNA attachment to Ribosomes Translation can be controlled by regulatory proteins that block mRNA attachment to the small subunit of the ribosome.
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Unformatted text preview: In humans, translation of the protein ferritin, an iron carrier, is blocked unless iron is present in the cell. Post Translation Processing After a polypeptide is synthesized it can be altered by processing. Many metabolic proteins are non-functional until activated by other molecules. Hydrolytic enzymes, in particular, are synthesized in inactive forms; membrane recognition proteins have additional molecules attached to them before they function. Protein Stability Proteins targeted for degradation are tagged by a tiny protein that is recognized by huge protease enzymes called proteasomes. The tagged protein is readily degraded within the proteasome. In cystic fibrosis, the chloride ion channel protein gets tagged and degraded before reaching the plasma membrane. Proteasomes...
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This note was uploaded on 12/29/2011 for the course BIO 151 taught by Professor Edwards during the Spring '10 term at SUNY Stony Brook.

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