PRR14 organizes H3K9me3-modified heterochromatin at the nuclear lamina

ABSTRACT

The eukaryotic genome is organized in three dimensions within the nucleus. Transcriptionally active chromatin is spatially separated from silent heterochromatin, a large fraction of which is located at the nuclear periphery. However, the mechanisms by which chromatin is localized at the nuclear periphery remain poorly understood. Here we demonstrate that Proline Rich 14 (PRR14) protein organizes H3K9me3-modified heterochromatin at the nuclear lamina. We show that PRR14 dynamically associates with both the nuclear lamina and heterochromatin, and is able to reorganize heterochromatin in the nucleus of interphase cells independent of mitosis. We characterize two functional HP1-binding sites within PRR14 that contribute to its association with heterochromatin. We also demonstrate that PPR14 forms an anchoring surface for heterochromatin at the nuclear lamina where it interacts dynamically with HP1-associated chromatin. Our study proposes a model of dynamic heterochromatin organization at the nuclear lamina via the PRR14 tethering protein.

KEYWORDS:

• PRR14
• heterochromatin
• nuclear lamina
• H3K9me3
• HP1
• FRAP

Acknowledgments

We thank Jonathan A. Epstein and Rajan Jain for support (NIH R35 HL140018 and DP2 HL147123) and for discussions and comments on the manuscript; Kelly Dunlevy, Jason Wasserman, Jade Wilson, Valentina Medvedeva, and Trinity Pellegrin for help with making certain constructs; Andrea Stout from the Penn CDB Microscopy Core for help with confocal imaging; Melike Lakadamyali for help with super-resolution imaging; Center for Engineering and Mechanobiology (CEMB) and NSF Science and Technology Center Pilot Award (CMMI 15-48571) for access to ONI super-resolution microscope and the Penn Flow Cytometry Core for technical support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

Conceptualization: A.A.K., R.A.K. and A.P. Methodology: A.A.K., Y.C., C.L.S., and A.P. Formal analysis: A.A.K. and A.P. Investigation: A.A.K., Y.C., and A.P. Visualization: A.A.K. and A.P. Data curation: A.A.K. and A.P. Resources: R.A.K. Supervision: A.P. Writing (original draft): A.P. Writing (review and editing): A.A.K, R.A.K., C.L.S., and A.P.

Data and materials availability

All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Raw western blot images are available as source data.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/19491034.2023.2165602

Additional information

Funding

This work was supported by the National Institutes of Health (NIH) R35 HL140018 and DP2 HL147123 supported A.P. and C.L.S., R21 AG054829 to R.A.K., and P30 CA006927 supported R.A.K., American Heart Association (AHA) 827458 to A.A.K.