A collaborative research team led by Professor Hyun Gyu Park’s research team from the Department of Chemical and Biomolecular Engineering has developed a new technology for the sensitive determination of ribonuclease H (RNase H) activity. The technology takes advantage of a highly efficient signal amplification reaction called the catalytic hairpin assembly (CHA) to effectively analyze RNase H activation. As RNase H is a key component of HIV propagation, this research could potentially contribute to the discovery of a cure for AIDS. The paper was published on the cover page of the 42nd issue of Nanoscale under the title “A label-free and enzyme-free signal amplification strategy for a sensitive RNase H activity assay”, with PhD students Chang Yeol Lee and Hyowon Jang as co-first authors.

Current RNase H activity assay technologies generally require fluorescent substances that are expensive and difficult to acquire. They also lack a method of signal amplification, leading to decreased sensitivity and efficiency. To overcome these limitations, Park’s team used a target-triggered CHA reaction to amplify the detection signal. RNase H triggers the execution of CHA by degrading the RNA in RNA/DNA duplexes, which releases the DNA that serves as the catalyst for CHA. The team engineered CHA to produce G-quadruplexes, which bind the G-quadruplex specific fluorescent binder N-methyl mesoporphyrin IX (NMM) to produce fluorescent signals. The promotion of efficient CHA by RNase H leads to the mass production of G-quadruplexes, which allows NMM to produce and amplify fluorescent signals. This technology also allows for the screening of RNase H inhibitors.

This research could become the key to finding a cure for AIDS. AIDS is caused by the retrovirus HIV, which uses reverse transcription to incorporate its genes into the host cell’s genome. The process of RNA being transcribed to DNA requires RNase H activity to function; That is, inhibiting the activation of RNase H can prevent the manifestation of HIV.

Professor Park stated, “The technology developed in this study is applicable to the development of various enzyme activity detection technologies besides RNase activity. We hope that it will become useful in diverse applications in the treatment of enzyme-related diseases.”