Regulation of gene expression in eukaryotes
Regulation of gene expression in eukaryotes
Regulation of gene expression in eukaryotes
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Post-transcriptional control cont.<br />
B. The stability <strong>of</strong> a class <strong>of</strong> mRNA can be controlled.<br />
‣ Some short-lived mRNAs have multiple copies <strong>of</strong> the<br />
sequence AUUUA which may act as a target for<br />
degradation.<br />
‣ the hormone prolact<strong>in</strong> enhances the stability <strong>of</strong> the<br />
mRNA for the milk prote<strong>in</strong> case<strong>in</strong><br />
‣ high levels <strong>of</strong> iron decrease the stability <strong>of</strong> the mRNA<br />
for the receptor that br<strong>in</strong>gs iron <strong>in</strong>to cells<br />
C. RNA <strong>in</strong>terference – poorly understood, but<br />
appears to be widespread <strong>in</strong> fungi, plants and<br />
animals as a regulatory mechanism<br />
‣ miRNAs & siRNAS (small RNA molecules) pair with<br />
prote<strong>in</strong>s to form an RNA-<strong>in</strong>duced silenc<strong>in</strong>g complex<br />
(RISC)<br />
‣ RISC pairs w/complentary base sequences <strong>of</strong> specific<br />
mRNAs and causes:<br />
6
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