Mechanism of riboswitch controlling mRNA splicing

A exciting research paper “Control of alternative RNA splicing and gene expression by eukaryotic riboswitches” published in Nature details the mechanism of how riboswitches work in Neurospora crassa. While riboswitches have been found and studied in bacteria there has not been extensive work showing how they work in fungi. In bacteria the riboswitch acts as the direct interacting sensor that switches gene expression off through a structural change in the RNA and fit in nicely with the RNA world view.

Using N. crassa, the authors show that alternative splicing is directly regulated through the thiamine metabolism genes which contains previously identified riboswitches. As also highlighted in the accompanying commentary this is also an interesting examples of direct RNA regulation of alternative splicing rather than through peptides like SR proteins.

The world’s largest organism

Take a guess: what’s the world’s largest organism? No, it’s not Yao Ming. While the Guiness Book of World Records hasn’t weighed in on this issue, scientists out of Oregon State University say that an Armillaria ostoyae individual residing in Oregon’s Blue Mountains is the largest living organism on the planet. Covering 2,200 acres, this tree killing fungus certainly is big. DNA fingerprinting and vegetative pairing confirm that a single individual spans this great distance. In addition to its great size, the fungus is quite old. By using growth rates to estimate age, this scientists estimate that this humongous fungus may be 8,000 years old.

While root rot, the tree killing phenomenon caused by A. ostoyae, slows the rate of tree harvest in a forest, the park service respects the organism’s vital role in the ecosystem. By clearing out old trees, fresh nutrients are resupplied to the soil and room is made for more resistant trees to grow. Besides, how do you kill something that is 1,600 football fields in size?