Potential G‐quadruplexes within the Promoter Nuclease Hypersensitive Sites of the Heat‐Responsive Genes in Rice. (20th September 2022) - Chang, Tianjun
Abstract: G‐quadruplexes (G4s) have been shown to be involved in the regulation of multiple cellular processes. Exploring putative G4‐forming sequences (PQSs) in heat‐responsive genes of rice and their folding structures under different conditions will help to understand the mechanism in response to heat stress. In this work, we discovered a prevalence of PQSs in nuclease hypersensitive sites within the promoters of heat‐responsive genes. Moreover, 50 % of the searched G3 PQSs ((G3+ L1‐7 )3+ G3+ ) locate in heat shock transcription factors. Circular dichroism spectroscopy, thermal difference spectroscopy, and UV melting analysis demonstrated the representative PQSs could adopt stable G4s at physiological temperature and potassium concentration. These PQSs were able to stall Klenow fragment (KF) DNA polymerase by the formation of G4s. However, the G4s with T m values around 50–60 °C could be increasingly unwound by KF with the increase of temperatures from 25 to 50 °C, implying that these G4s could sense the changes in temperature by structural switch. This work offers fresh clues to understanding the potential of G4‐involved functions of PQSs and the molecular events in plants in response to heat stress. Abstract : G‐quadruplex‐forming sequences are prevalent in the promoter nuclease hypersensitive sites of rice heat‐responsive genes. These sequences can adopt a G4 conformation to stall DNA polymerase, but become increasingly unwound by the polymerase with a rise in temperature, implying a potential for these sequences to function as "thermosensors" in response to heat.