It turns out there is one more reason extra fat in our diet just isn’t good for you – excess fat can trigger cell suicide. Recently, Jean Schaffer’s group at Washington University have identified a very special RNA that responds to excess fat in the cell.
Do you think the cheese in the crust is like the nucleus of a cell?
I had to put this in because when I mentioned stuffed-crust,
I wanted stuffed-crust.
Generally, when you eat a double-stuffed Oreo, adipose tissue or fat, which is made of professional fat-loving storage cells, mop up excess stuffed-crust pizza calories circulating in the blood. Unfortunately, adipose tissue has a limit and cannot cope with all of the fat presented to it and this extra fat circulates in your bloodstream. When extra fat is floating around the body other, non-professional fat-impartial cells take up the fat & this disrupts their normal cell cycle leading to cell suicide. In the medicine world, “this cellular kamikaze can lead to kidney and heart failure”.
The pathway to fat-triggered cell suicide was unknown until Schaffer’s group determined there was a single gene that was responsible. After looking further into the gene they determined it did not encode a protein, but a type of RNA molecule called small nucleolar RNA (snoRNA – which unfortunately is not pronounced SNOR-NA, but instead snow RNA).
snoRNAs are a class of small RNA molecules that modify other RNAs, mostly RNAs found in the nucleus, where they live. However, this special snoRNA was fluorescently labeled (my favorite!) and found in the cytoplasm. At first one would think that well this RNA was just misnamed, and can no longer be a snoRNA if it’s not in the nucleus, but the researchers hold that this particular snoRNA may have more than one function (that because of their name, no one ever cared to look for). They also show that this snoRNA can also mediate general cell stress (by looking at hydrogen peroxide stress or reactive-oxygen species induced stress).
The snoRNA (red) can be seen outside of the nucleus (green) in these cells.
In addition, this provides insights into yet ANOTHER interesting and unique function of RNAs, one of the more magical molecules on the universe.
Quote from: Science Blog Article
Michel CI, Holley CL, Scruggs BS, Sidhu R, Brookheart RT, Listenberger LL, Behlke MA, Ory DS, & Schaffer JE (2011). Small Nucleolar RNAs U32a, U33, and U35a Are Critical Mediators of Metabolic Stress. Cell metabolism, 14 (1), 33-44 PMID: 21723502