Scientists One Step Closer To Re-Create Four Billion Year Old ‘RNA World’

A team of scientists from The Scripps Research Institute (TSRI) claim that they have taken a big step towards re-creating the "RNA world" of four billion years ago in the laboratory. They have successfully created a ribozyme that is capable of amplifying genetic information as well as generating functional molecules.

According to the scientists, the newly created enzyme, described in the paper published in the journal Proceedings of the National Academy of Science, can efficiently replicate short lengths of RNA and even perform transcription on longer RNAs to make functional RNA molecules with complex structures. The TRSI team used test-tube evolution techniques to accomplish the task of creating an enzyme that could both replicate and transcribe RNA and thus support an RNA world, reported Phys.org.

Senior author of the study, Gerald F. Joyce, who is a professor at TSRI, said that this is probably the first time ever that they have synthesized some of the complex RNA molecules with a ribozyme [a special RNA enzyme] since the end of the RNA world four billion years ago. The research team, led by Joyce and David P. Horning, began with a variant of the class I RNA polymerase ribozyme. They drew upon several improvements described in previous research and introduced random mutations to create a population of roughly 100 trillion distinct variants of the molecule.

From the different variants, the researchers selected ribozymes which was capable of producing two different and challenging RNA molecules. After two dozen rounds of selection, the best performer, polymerase ribozyme 24-3, proved to be capable of synthesizing the two target-binding RNAs as well as several other structurally complex RNA molecules. The scientists found that polymerase ribozyme 24-3 also has the ability to stitch together RNA sequences about 100 times faster than the class I RNA polymerase ribozyme. Furthermore, it was also found that ribozyme 24-3 could copy RNAs of up to two dozen nucleotides and create as many as 40,000 copies of a target RNA within 24 hours, reported Nature World News.

The researchers will now strive to search for more ways to improve the new ribozyme to replicate longer, more complex RNA molecules in order to generate and sustain true RNA World.