A report on the renegade ribonucleic acid, and the code that directs its movement, will be published Jan. 5 in Science.
MicroRNAs, already implicated in cancer and normal development, latch on to and gum up larger strands of RNA that carry instructions for making the proteins that do all the cell's work. They are, says Joshua Mendell, M.D., Ph.D., an assistant professor in the McKusick-Nathans Institute of Genetic Medicine at Hopkins, like "molecular rheostats that fine-tune how much protein is being made from each gene."
That's why normally microRNAs always have appeared to stick close to the cell's protein-making machinery.
But during a survey of more than 200 of the 500 known microRNAs found in human cells, Mendell's team discovered one lone microRNA "miles away" --- in cellular terms --- from all the others.
"It was so clearly in the wrong place at the wrong time for what we thought it was supposed to be doing that we just had to figure out why," says Hun-Way Hwang, a graduate student in human genetics and contributor to the study.
Consisting of only 20 to 25 nucleotide building blocks (compared to other types of RNA that can be thousands of nucleotides long), each microRNA has a different combination of blocks. Mendell's team realized that six building blocks at the end of the wayward miR-29b microRNA were noticeably different from the ends of other microRNAs.
Suspicious that the six-block end might have something to do with miR-29b's location, the researchers chopped them off and stuck them on the end of another microRNA. When put into cells, the new microRNA behaved just like miR-29b, wandering far away from the cell's protein-making machinery and into the nucleus, where the cell's genetic material is kept.
The researchers then stuck the same six-block end onto another type of small RNA, a small-interfering RNA or siRNA that turns off genes. This also forced the siRNA into the nucleus.
According to Mendell, these results demonstrate for the first time that despite their tiny size, microRNAs contain elements consisting of short stretches of nucleotide building blocks that can control their behavior in a cell. Mendell hopes to take advantage of the built-in "cellular zip code" discovered in miR-29b as an experimental tool. For example, he plans to force other microRNAs and siRNAs into the nucleus to turn off specific sets of genes.
Mendell's team is actively hunting for additional hidden microRNA elements that control other aspects of their behavior in cells. They also are curious to figure out what miR-29b is doing in the nucleus. Because microRNAs have been implicated in cancer as well as normal development, Mendell hopes that further study of miR-29b will reveal other, hidden functions of microRNAs.
Audrey Huang | EurekAlert!
How molecules teeter in a laser field
18.01.2019 | Forschungsverbund Berlin
Discovery of enhanced bone growth could lead to new treatments for osteoporosis
18.01.2019 | University of California - Los Angeles
The scientific and political community alike stress the importance of German Antarctic research
Joint Press Release from the BMBF and AWI
The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
18.01.2019 | Materials Sciences
18.01.2019 | Life Sciences
18.01.2019 | Health and Medicine