RNA triplex structures and genetic information

16.01.2023

Published in Nucleic Acids Research, the study “Rational design of hybrid DNA–RNA triplex structures as modulators of transcriptional activity in vitro” was conducted by an international team led by Alessandro Cecconello of the Department of Comparative Biomedicine and Nutrition of the University of Padua and researchers from the University of Munich.

The study is the first to present a general approach to the analysis of the regulatory mechanism of gene transcription, which is the conversion of DNA into RNA. The study shows how it is possible to determine the inhibition or increase of this conversion through the formation of triplex hybrids, ultimately resulting in the switching off or the activation of that gene. The research uses synthetic RNA strands as the control of gene expression from transcriptional units produced in vitro (units composed of a regulatory and a transcribed part) that are designed from bacterial DNA.

DNA and RNA nucleic acids are linear polymers commonly found in single-stranded or duplex (double-stranded helix) cells that store and transmit genetic information. Although these polymers can assume other geometries such as triplex (three strands) or quadruplex (four strands), little is known about their biological functions. The hybrid triplex, which is a triple-helix structure, composed of a DNA or RNA duplex and a single strand of another nucleic acid appears to be involved in regulatory mechanisms.

The hybrid triple-helix structures are the subject of intense studies, much of which concerns the long non-coding RNA (lncRNAs) which are single-stranded RNA molecules that do not encode proteins. Such molecules seem to be involved in the regulation of specific genes based on a mechanism of inhibition or stimulation of transcription involving triple-helix structures.