Abstract
Somatic cell reprogramming is an ideal model for studying epigenetic regulation as it undergoes dramatic chromatin remodeling. However, a role for phosphorylation signaling in chromatin protein modifications for reprogramming remains unclear. Here, we identified mitogen-activated protein kinase kinase 6 (Mkk6) as a chromatin relaxer and found that it could significantly enhance reprogramming. The function of Mkk6 in heterochromatin loosening and reprogramming requires its kinase activity but does not depend on its best-known target, P38. We identified Gatad2b as a novel target of Mkk6 phosphorylation that acts downstream to elevate histone acetylation levels and loosen heterochromatin. As a result, Mkk6 over-expression facilitates binding of Sox2 and Klf4 to their targets and promotes pluripotency gene expression during reprogramming. Our studies not only reveal an Mkk phosphorylation mediated modulation of chromatin status in reprogramming, but also provide new rationales to further investigate and improve the cell fate determination processes.
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Data availability
The Sequencing data reported in this paper has been deposited in the Genome Sequence Archive at the Beijing Institute of Genomics (BIG) Data Center, BIG, Chinese Academy of Sciences. The accession numbers for the ATAC-seq, ChIP-seq and RNA-seq data in this study are CRA005167, CRA005151 and CRA005159, which are publicly accessible at https://bigd.big.ac.cn/gsa.
Change history
10 December 2021
A Correction to this paper has been published: https://doi.org/10.1038/s41418-021-00923-8
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Acknowledgements
We thank all the members in the labs of Prof DP and Prof XL. This work was financially supported by the National Key Research and Development Program of China (2018YFA0107100), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16030505), the National Key Research and Development Program of China (2017YFA0106300, 2017YFA0102900, 2017YFA0504100, 2019YFA0904500), the National Natural Science Foundation projects of China (32025010, 31900614, 31970709, 81901275, 32070729, 32100619, 32170747, 31830060), the Key Research Program of Frontier Sciences, CAS (QYZDB-SSW-SMC001), and International Cooperation Program, CAS (154144KYSB20200006), Guangdong Province Science and Technology Program (2020B1212060052, 2018A030313825, 2018GZR110103002, 2020A1515011200, 2020A1515010919, 2020A1515011410, 2021A1515012513), Guangzhou Science and Technology Program (201807010067, 202002030277, 202102020827, 202102080066), Open Research Program of Key Laboratory of Regenerative Biology, CAS (KLRB201907, KLRB202014), and CAS Youth Innovation Promotion Association (to YW).
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DP, XL, and KC supervised the project. DP, KC, and TW initiated wild-type and mutant Mkk6 effects on reprogramming efficiency. DP, XL, KC, GX, and DZ identified Mkk6’s function depends on not P38 but Gatad2b, a novel target which acts downstream to elevate histone acetylation levels, loosen heterochromatin and facilitate binding of Sox2 and Klf4 to their targets and promotes pluripotency gene expression during reprogramming. XL, KC, DZ, GX, ZL, and HY designed and performed iPSCs generation, ITRAQ, co-IP, western blot, RNA-seq, ChIP-qPCR, ChIP-seq, ATAC-seq, in vitro kinase assay, nuclease accessibility assay and salt extraction assay. LH, ZH, YL, JLu, and SL participated in plasmids construction, iPSCs generation, and the dependence of Mkk6 function on P38. YW, LL, JZ, JW, and BW participated in cell culture and ChIP-qPCR. QL and YZ participated in FRAP and HP1α immunofluorescence. JLiu and JC participated in chimeric mice and germline transmission mice generation. DP, XL, KC, GX, ZL, and DZ wrote the paper. All authors contributed to the writing and editing of the paper and approved the final paper.
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All the cells were obtained with approval from the ethics committee of the Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences (GIBH). All the animals were handled according to approved Institutional Animal Care and Use Committee protocols of the GIBH.
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Xing, G., Liu, Z., Huang, L. et al. MAP2K6 remodels chromatin and facilitates reprogramming by activating Gatad2b-phosphorylation dependent heterochromatin loosening. Cell Death Differ 29, 1042–1054 (2022). https://doi.org/10.1038/s41418-021-00902-z
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DOI: https://doi.org/10.1038/s41418-021-00902-z
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