Plant RNAs Impact Gene Expression in Mammals
Short RNA sequences (microRNA) from plants have been found in mammals, with recent news that they can influence gene expression in humans. One microRNA found in rice restricts a protein that helps remove particles linked to bad cholesterol.
Chen-Yu Zhang, a molecular biologist at Nanjing University in China, was studying the role of circulating microRNAs in health and disease when he discovered that microRNAs are present in other bodily fluids such as milk. This gave him the “crazy idea” that exogenous microRNAs, such as those ingested through the consumption of milk, could also be found circulating in the serum of mammals, he recalled.
To test his hypothesis, Zhang and his team of researchers sequenced the blood microRNAs of 31 healthy Chinese subjects and searched for the presence of plant microRNAs. Because plant microRNAs are structurally different from those of mammals, they react differently to oxidizing agents, and the researchers were able to differentiate the two by treating them with sodium periodate, which oxidizes mammal but not plant microRNAs.
To their surprise, they found about 40 types of plant microRNAs circulating in the subjects’ blood—some of which were found in concentrations that were comparable to major endogenous human microRNAs.
By identifying the function of plant RNA in gene expression, scientists can further determine how diet impacts our health positively or–as in the case of rice on cholesterol–negatively.