And now, while studying the mechanism behind RNAi researchers at Oxford and Helsinki University have discovered that the functional core of a key enzyme (enzymes are proteins which promote biochemical reactions in the body) involved in the formation of RNAi molecules is striking similar to an enzyme involved in gene expression.
The research, published in the journal "Public Library of Science Biology", supports the idea that the two enzymes have a common ancestor and gives weight to the theory that life started as self-replicating RNA molecules in a RNA world (as opposed to the present world where molecules of DNA are the basis of life).
In fact, we live in a DNA world, as genes are segments of DNA, and it is the information contained in the genes of an organism that, when translated into proteins, makes up the blueprint for the body structure and function. This process, the expression of genes into proteins, is comprised of two steps: the first by which genetic information in DNA is converted into RNA and the second which is the synthesis of proteins based on the information/instructions contained in the newly made RNA (DNA ? RNA ? protein).
But there is a dent in this apparently perfect process. In fact, for a long time scientists have been puzzled why approximately 32% of the human genome/DNA, although transformed into RNA, does not lead to protein production (DNA ? RNA ? no protein)? So why would this huge amount of “junk” RNA keep being formed instead of being eliminated during evolution? After all, a basic rule of life is that any reaction that costs energy and is not advantageous for the individual must be eliminated. What recent research unveiled is that RNA is a much more multifaceted molecule than previously thought, and some of that “junk” RNA actually plays an important role in gene regulation. One such example is RNAi, a RNA that is capable of blocking the activity of specific genes.
And it was while studying the mechanisms behind RNAi, that Paula S. Salgado, Jonathan M. Grimes and colleagues discovered that the functional core of an enzyme involved in the formation of short RNAi molecules from other RNA molecules (RNA? RNA), was remarkably similar to the one that mediates the formation of RNA from DNA (DNA ? RNA) during the first step of gene expression. This striking similarity suggested a common ancestor and further analysis seemed to indicate that the enzyme involved in the RNAi process had appeared before and so would probably be more similar structurally to the common ancestor.
These results support the idea of life starting in a (RNA) world where self-replicating (RNA?RNA) multifunctional RNA molecules evolved (as well as the enzymes mediating the process) into the present situation where genetic information is contained instead on DNA. In fact, although RNA is chemically similar to DNA it has, as the “originater” of life, two major advantages over the latter molecule: 1- it is easily synthesised from non-complex blocks so it had higher possibility of occurring spontaneously and 2 - it is easy to imagine that it could evolve into DNA, which by being a much more stable molecule would then take over. Furthermore, the idea of a primitive RNA world, if proved, could solve one of biggest conundrums on the origin of life: if life needs both DNA as a source of genetic information and proteins to drive life’s chemical reactions how could have one appeared first without the other? Some scientists believe that the answer lies in this ancient RNA molecule which was capable of supporting life reactions and also contained life’s genetic blueprint and whose existence seems to be consistent with the findings of Salgado, Grimes and colleagues.
In this way, Salgado’s work sheds light not only on the mechanism behind this extremely interesting and important process that is RNAi, but can also help to understand better how life began on earth.Piece researched and written by:
Catarina Amorim | alfa
Scientists unlock ability to generate new sensory hair cells
22.02.2017 | Brigham and Women's Hospital
New insights into the information processing of motor neurons
22.02.2017 | Max Planck Florida Institute for Neuroscience
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
22.02.2017 | Power and Electrical Engineering
22.02.2017 | Life Sciences
22.02.2017 | Physics and Astronomy