An R-loop is a three-stranded nucleic acid structure; composed of a DNA:RNA hybrid and the associated non-template single-stranded DNA. R-loops may have formtaion in a variety of circumstances, and may be tolerated or cleared by cellular components. The term “R-loop” was given to reflect the similarity of these structures to D-loops; the “R” in this case represents the involvement of an RNA moiety. In the laboratory; R-loops may also be created by the hybridization of mature mRNA with double-stranded DNA; under conditions favoring the formation of a DNA-RNA hybrid.
In this case, the intron regions (which have been spliced out of the mRNA) form single-stranded loops; as they cannot hybridize with complementary sequence in the mRNA. Scientists have shed light on how healthy cells develop by identifying the role of key molecules involved. The components, known as R-loops; formed during cell development and; shown to play an important role in the process. The latest finding overturns previous thinking that R-loops; formed from the genetic material that makes up DNA; were harmful to cells. Researchers found that R-loops work togeter with a group of cell proteins, known as Polycomb, to control genes that are important for development in humans and other mammals.
Examining R-loops in developing brain cells
Further research could clarify the role of R-loops in diseases in which they have association. These include neurogenerative disorders such as Amyotrophic Lateral Sclerosis (ALS) and the developmental condition Fragile X. Future studies may include examining R-loops in developing brain cells; with a view to informing the design of drugs to treat these neurological conditions. The findings also have important implications for some cancers; which has association with faulty Polycomb proteins or the over-production of R-loops.
So, the study, published in Molecular Cell; carried out in collaboration between the Max Delbruck Centre for Molecular Medicine in Berlin and the University of Edinburgh; supported by Wellcome and the European Research Council. Dr Konstantina Skourti-Stathaki, of the University of Edinburgh’s School of Biological Sciences, who led the study, said: “This new insight answers fundamental questions, opening new avenues for future research and possible routes towards drug treatments.”