Function
Sib RNA regulates the expression of a toxic protein in a type I toxin-antitoxin system similar to that of hok/sok andldr-rdl genes. The constitutively expressed Sib transcript regulates the ibs (induction brings stasis) open reading frame which encodes a small 18-19 amino acid hydrophobic protein which slows growth at moderate levels of expression and is toxic when overexpressed. The ibs gene is on the opposite strand to sib and is completely complimentary, so the antisense-binding of Sib RNA with the ibs mRNA brings about dsRNA-mediated degradation.
When sib was deleted in multi-copy plasmids, the cells could not be maintained due to the toxicity of the unrepressed ibs protein. The toxicity mechanism of ibs protein is not fully understood, but a change in membrane potential upon over-expression of the protein suggests that interactions with membrane proteins or membrane insertion brings about cell death.
Read more about this topic: Sib RNA
Famous quotes containing the word function:
“The fact remains that the human being in early childhood learns to consider one or the other aspect of bodily function as evil, shameful, or unsafe. There is not a culture which does not use a combination of these devils to develop, by way of counterpoint, its own style of faith, pride, certainty, and initiative.”
—Erik H. Erikson (1904–1994)
“Our father has an even more important function than modeling manhood for us. He is also the authority to let us relax the requirements of the masculine model: if our father accepts us, then that declares us masculine enough to join the company of men. We, in effect, have our diploma in masculinity and can go on to develop other skills.”
—Frank Pittman (20th century)
“The press and politicians. A delicate relationship. Too close, and danger ensues. Too far apart and democracy itself cannot function without the essential exchange of information. Creative leaks, a discreet lunch, interchange in the Lobby, the art of the unattributable telephone call, late at night.”
—Howard Brenton (b. 1942)