A number of microRNAs can repress translation of Twist1, a proto-oncogene whose upregulation is linked to resistance to cancer drugs, report Aarhus University researchers in PLOS One. In a number of cell lines, the researchers found that miR-145a-5p, miR-151-5p and a combination of miR-145a-5p and miR-151-5p or of miR-151-5p and miR-337-3p could repress the expression of the oncogene. "The additive and synergistic effects of these miRNAs could reduce unwanted 'off target' effects and might open up new possibilities to specifically interfere with TWIST1 translation in therapeutic approaches," the researchers note.
Stanford University's Dmitri Petrov and his colleagues there and at the Technion-Israel Institute of Technology examined site frequency spectra from sequencing data from a large population of fruit flies. They found that 22 percent of four-fold degenerate sites in the Drosophila melanogaster genome appear to be under strong selective pressure. "With the discovery of a significant fraction of sites under strong constraint in Drosophila, two things become clear: the role of synonymous sites in the biology of genomes is far greater than the neutral, 'silent' part they were once assumed to play; and we still have much to learn about the functionality encoded in genes," they write in PLOS Genetics.
Virginia Tech's Zach Adelman and his colleague report in PLOS Neglected Tropical Diseases that that temperature affects RNAi machinery and may make mosquitoes more vulnerable to infection by viruses. The group studied the RNA silencing pathway in Aedes aegypti grown at different temperatures. A transgenic sensor strain of A. aegyti grown at 18°C, the team reports, showed impaired RNAi machinery. Further, mosquitoes grown at the cooler temperature had higher infection rates for both the chikungunya and yellow fever viruses.