An antagonistic epigenetic mechanism regulating gene expression in pollen revealed through single-nucleus multiomics

Picard, C. L.; Ichino, L.; Buckley, T. J.; Boone, B. A.; Abuhanna, K. D.; Zhang, Y.; Behrendt, N. J.; May Lei Soe, S.; Luo, C.; Jacobsen, S. E.

doi:10.1101/2025.10.13.682236

bioRxiv · 10.1101/2025.10.13.682236

An antagonistic epigenetic mechanism regulating gene expression in pollen revealed through single-nucleus multiomics

Picard, C. L.·Ichino, L.·Buckley, T. J.·Boone, B. A.·Abuhanna, K. D.·Zhang, Y.·Behrendt, N. J.·May Lei Soe, S.·Luo, C.·Jacobsen, S. E.

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Abstract

Arabidopsis MBD5, MBD6, and MBD7 are CG-specific methyl-readers with opposite functions: MBD5 and MBD6 (MBD5/6) repress methylated loci in pollen vegetative nuclei (VN), while MBD7 prevents transgene silencing, possibly by promoting DNA demethylation. Here we show that loss of MBD7 rescues transcriptional defects at a large subset of MBD5/6-bound loci. Using simultaneous profiling of DNA methylation and transcription in single pollen nuclei, we found that MBD5/6-bound loci that are actively demethylated in immature VN lose additional methylation in mbd5/6, prior to transcriptional derepression. A subset of these loci is also bound by MBD7, correlating with demethylation and transcriptional derepression in mbd5/6 that are both reversed by loss of MBD7. Conversely, ectopically recruiting the MBD7 complex to MBD5/6 targets causes partial demethylation and upregulation. We propose that MBD5/6 maintain silencing in VN in part by preventing the MBD7 complex from enhancing the active demethylation that occurs during VN maturation.

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Picard, C. L., Ichino, L., Buckley, T. J., Boone, B. A., Abuhanna, K. D., Zhang, Y., Behrendt, N. J., May Lei Soe, S., Luo, C., Jacobsen, S. E.. 2025-10-15. An antagonistic epigenetic mechanism regulating gene expression in pollen revealed through single-nucleus multiomics. https://doi.org/10.1101/2025.10.13.682236

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