New Results
, Xiangyou Pi, Ziwei Lv, Tianliang Liu, Huajun Yin, Danni Shi, Muxi Li, Juan Du, Yanchao Yang, Shiyu Wang, Peng Wang, Yangmei Qin, Wenbo Lin, Tao Tao, Ling Sun, Wenfeng Chen, Xi Zhang, Yufeng Yang, Zhiliang Ji
doi: https://doi.org/10.64898/2025.12.08.692888
Abstract
For decades, the 5’→3’ direction of translation has been a central dogma of molecular biology(1). Here we present evidence that eukaryotic circular RNAs (circRNAs) can serve as templates for 3’→5’ backward translation (BT), yielding polypeptides with distinct sequence and structural features not found in canonical proteomes. Mining of more than 6,000 multi-omics datasets identified ∼1 million candidate BT proteins across eukaryotes, including 59,000 high-confidence human BT proteins supported by mass spectrometry. Genetic combinatorial experiments (KO and KI) and cell-free translation of synthetic circRNAs establish BT as a conserved mechanism. Loss-of-function studies of hs.circCAPN15 in human and dm.circROLS in Drosophila underscore the functional importance of BT-derived proteins. Our work challenges the long-standing unidirectional translation paradigm, expands the functional landscape of the genetic code, and reveals a hitherto hidden layer of proteomic complexity with broad implications for biology and therapeutics.
Competing Interest Statement
The authors have declared no competing interest.
Funder Information Declared
Ministry of Science and Technology of the People's Republic of China, 2024YFF1206802
National Natural Science Foundation of China, https://ror.org/01h0zpd94, 32170658, 32200959
Copyright
The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC 4.0 International license.