Genna, VitoPortella, GuillemSala, AlbaTerrazas Martínez, MontserratSerrano Chacón, IsraelGonzalez-Díaz, JoaquínVillegas, NúriaMateo, LidiaCastellazzi, ChiaraLabrador, MireiaAviño, AnnaHospital, AdamGandioso, AlbertAloy, PatrickBrun-Heath, IsabelleGonzalez, CamilleEritja i Casadellà, RamonOrozco López, Modesto2025-09-052025-09-052025-03-240305-1048https://hdl.handle.net/2445/222994By combining in silico, biophysical, and in vitro experiments, we decipher the topology, physical, and potential biological properties of hybrid-parallel nucleic acids triplexes, an elusive structure at the basis of life. We found that hybrid triplex topology follows a stability order: r(Py)-d(Pu)·r(Py) > r(Py)-d(Pu)·d(Py) > d(Py)-d(Pu)·d(Py) > d(Py)-d(Pu)·r(Py). The r(Py)-d(Pu)·d(Py) triplex is expected to be preferred in the cell as it avoids the need to open the duplex reducing the torsional stress required for triplex formation in the r(Py)-d(Pu)·r(Py) topology. Upon a massive collection of melting data, we have created the first predictor for hybrid triplex stability. Leveraging this predictor, we conducted a comprehensive scan to assess the likelihood of the human genome and transcriptome to engage in triplex formation. Our findings unveil a remarkable inclination—of both the human genome and transcriptome—to generate hybrid triplex formation, particularly within untranslated (UTRs) and regulatory regions, thereby corroborating the existence of a triplex-mediated regulatory mechanism. Furthermore, we found a correlation between nucleosome linkers and Triplex-forming sequence (TFS) which agree with a putative role of triplexes in arranging chromatin structure.14 p.application/pdfengcc-by-nc (c) Genna, V. et al., 2025http://creativecommons.org/licenses/by-nc/4.0/Àcids nucleicsGenoma humàNucleic acidsHuman genomeinfo:eu-repo/semantics/article7601072025-09-05info:eu-repo/semantics/openAccess6728702