The POU family transcription factor Oct4 plays pivotal roles in regulating pluripotency and somatic cell reprogramming. Previous studies have indicated an important role for major groove contacts in Oct4-DNA recognition; however, the contributions of the RK motif in the POUh domain and the linker segment joining the two DNA-binding domains remain poorly understood.

By combining molecular modelling, biochemical and functional assays, the researchers in Shanghai Institute of Materia Medica (SIMM), CAS find that the RK motif is essential for Oct4-DNA association by recognizing the narrowed DNA minor groove. Intriguingly, computational simulations reveal that the function of the RK motif may be finely tuned by H-bond interactions with the linker segment and that breaking these interactions significantly enhances the DNA binding and reprogramming activities of Oct4. These findings uncover a self-regulatory mechanism for specific Oct4-DNA recognition and provide insights into the functional crosstalk at the molecular level that may illuminate mechanistic studies of the Oct protein family and possibly transcription factors in the POU family. The gain-of-function Oct4 mutants might also be useful tools for use in reprogramming and regenerative medicine.

This study has been published recently in the Nucleic Acids Research. Dr. KONG Xiangqian under the supervision of Prof. LUO Cheng and Ph.D. candidate LIU Jian under the supervision of Prof. XIE Xin from SIMM contributed equally to this work.

This study was supported by grants from the Ministry of Science and Technology of China, Chinese Academy of Sciences, and National Natural Science Foundation of China. The computational resources were provided by the Computer Network Information Center of Chinese Academy of Sciences, Tianjin Supercomputing Center and Shanghai Supercomputing Center.