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Defying Textbook Science, Study Finds Proteins Built Without DNA Instructions

Posted on January 3, 2015  Comments (2)

Open any introductory biology textbook and one of the first things you’ll learn is that our DNA spells out the instructions for making proteins, tiny machines that do much of the work in our body’s cells. Results from a recent study show for the first time that the building blocks of a protein, called amino acids, can be assembled without blueprints – DNA and an intermediate template called messenger RNA (mRNA). A team of researchers has observed a case in which another protein specifies which amino acids are added.

“This surprising discovery reflects how incomplete our understanding of biology is,” says first author Peter Shen, Ph.D., a postdoctoral fellow in biochemistry at the University of Utah. “Nature is capable of more than we realize.”

To put the new finding into perspective, it might help to think of the cell as a well-run factory. Ribosomes are machines on a protein assembly line, linking together amino acids in an order specified by the genetic code. When something goes wrong, the ribosome can stall, and a quality control crew is summoned to the site. To clean up the mess, the ribosome is disassembled, the blueprint is discarded, and the partly made protein is recycled.

Yet this study reveals a surprising role for one member of the quality control team, a protein conserved from yeast to man named Rqc2. Before the incomplete protein is recycled, Rqc2 prompts the ribosomes to add just two amino acids (of a total of 20) – alanine and threonine – over and over, and in any order. Think of an auto assembly line that keeps going despite having lost its instructions. It picks up what it can and slaps it on.

“In this case, we have a protein playing a role similar to that filled by mRNA,” says Adam Frost, M.D., Ph.D., assistant professor at University of California, San Francisco (UCSF) and adjunct professor of biochemistry at the University of Utah. He shares senior authorship with Jonathan Weissman, Ph.D., a Howard Hughes Medical Institute investigator at UCSF, and Onn Brandman, Ph.D., at Stanford University. “I love this story because it blurs the lines of what we thought proteins could do.”

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Given Tablets but No Teachers, Kids Teach Themselves – Having Never Seen Advanced Technology Before

Posted on May 3, 2013  Comments (5)

In a repetition of an experiment I have posted about here on the Curious Cat Science and Engineering Blog before (Letting Children Learn – Hole in the Wall Computers): Given Tablets but No Teachers, Ethiopian Children Teach Themselves

The experiment is being done in two isolated rural villages with about 20 first-grade-aged children each, about 50 miles from Addis Ababa. One village is called Wonchi, on the rim of a volcanic crater at 11,000 feet; the other is called Wolonchete, in the Great Rift Valley. Children there had never previously seen printed materials, road signs, or even packaging that had words on them, Negroponte said.

Earlier this year, OLPC workers dropped off closed boxes containing the tablets, taped shut, with no instruction. “I thought the kids would play with the boxes. Within four minutes, one kid not only opened the box, found the on-off switch … powered it up. Within five days, they were using 47 apps per child, per day. Within two weeks, they were singing ABC songs in the village, and within five months, they had hacked Android,” Negroponte said. “Some idiot in our organization or in the Media Lab had disabled the camera, and they figured out the camera, and had hacked Android.”

Nicholas Negroponte has tendency to overstate the fact from what I remember. I don’t think what he claims as “hacking Android” here is what a real scientist would claim as than is a write up of the results of the experiment. He could well mean they updated a setting or some similar thing. It is a shame to mislead when the bare facts are so cool. And possibly he isn’t misleading – I just am worried he is.

Also what does 47 apps per day mean? I can’t understand how you can usefully (including entertainment do that in any sensible way) – I doubt I use 15 applications in a month and I use the computer hours every single day. Makes me worry that “using” is not a very enlightening piece of data – instead just trying to make it seem like using 47 must mean they are engaged; it seems more likely to me to mean they are not used successfully so they have to go try something else or they are counting “used” in ways we wouldn’t.

Once a week, a technician visits the villages and swaps out memory cards so that researchers can study how the machines were actually used.

These kinds of experiments are very cool. They show how intrinsically curious we are are. Sadly our schools often beat the curiosity out of kids instead of engaging it.

Related: What Kids can Learn (look at the same idea in 2006) – Providing Computer to Remote Students in Nepal (2009) – $100 Laptops for the World