Reporter assays for studying quadruplex nucleic acids.

DNA and RNA G-quadruplexes have gained increasing attention due to their potential role in a wide range of biological functions. The majority of functional studies characterize the influence of quadruplexes in gene expression including transcription and translation. Many of these studies have used reporter assays to elucidate the effect of quadruplexes at certain positions in promoters and untranslated mRNA regions (UTRs). Reporter assays are the preferred method to ascertain the biological function of DNA or RNA G-quadruplexes intracellularly due to their ready availability, fast cloning and experimental setup and reproducibility. Moreover, these reporter assays are also helpful to compare or screen for selectivity and efficacy of small molecules that target DNA and RNA G-quadruplexes in the cellular context. Here we briefly discuss various aspects of reporter assays followed by a review of available studies using reporter assays to understand the role and functions of DNA and RNA quadruplexes in gene expression.