Protamine expression in somatic cells condenses chromatin and disrupts transcription without altering DNA methylation

bioRxiv (Cold Spring Harbor Laboratory)

Abstract

Abstract Protamines play a crucial role in nuclear condensation during spermiogenesis, a process that involves significant chromatin remodeling and the replacement of histones. While much research has focused on the function of protamines in sperm development and fertility, their effects in non-sperm cells remain largely unexplored. In this study, we investigated the impact of overexpressing murine and human protamine 1 and 2 (PRM1 and PRM2) on nuclear architecture, histone eviction, DNA methylation, and transcription in HEK293T cells and mesenchymal stromal cells (MSCs). Overexpression of protamines resulted in nuclear condensation; particularly PRM1 showed notable enrichment in nucleoli, and cells exhibited cell cycle abnormalities. Immunofluorescence staining indicated a significant reduction in specific histone modifications (H3K9me3, H3K4me1, and H3K27Ac) in response to protamine expression, especially in MSCs. Interestingly, despite these changes in nuclear organization, the methylome remained largely stable. However, expression of protamines significantly diminished transcription, particularly of the ribosomal genes, upon PRM1 expression. Our studies indicate that PRM1 and PRM2 condense distinct genomic regions in somatic cells, resulting in widespread silencing of gene expression.

Authors 7

1. Deepika Puri corresponding Aachen Medical Faculty Institute of Stem Cell Biology Institute of Stem Cell Biology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Helmholtz-Institute for Biomedical Engineering, Medical Faculty of RWTH Aachen University, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospital of RWTH Aachen, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospitl of RWTH Achen, 52074 Achen, Germny

2. Alexandra Bott Aachen Medical Faculty Institute of Stem Cell Biology Institute of Stem Cell Biology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Helmholtz-Institute for Biomedical Engineering, Medical Faculty of RWTH Aachen University, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospital of RWTH Aachen, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospitl of RWTH Achen, 52074 Achen, Germny

3. Monica Varona Baranda Aachen Medical Faculty Institute of Stem Cell Biology Institute of Stem Cell Biology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Helmholtz-Institute for Biomedical Engineering, Medical Faculty of RWTH Aachen University, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospital of RWTH Aachen, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospitl of RWTH Achen, 52074 Achen, Germny

4. Esra Dursun Torlak Aachen Medical Faculty Institute of Stem Cell Biology Institute of Stem Cell Biology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Helmholtz-Institute for Biomedical Engineering, Medical Faculty of RWTH Aachen University, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospital of RWTH Aachen, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospitl of RWTH Achen, 52074 Achen, Germny

5. Gina Esther Merges

   University of Bonn · University Hospital Bonn

   Affiliation as printed

   Department of Developmental Pathology, Institute of Pathology, University Hospital Bonn, 53127 Bonn, Germany

6. Hubert Schorle

   University of Bonn · University Hospital Bonn

   Affiliation as printed

   Department of Developmental Pathology, Institute of Pathology, University Hospital Bonn, 53127 Bonn, Germany

7. Wolfgang Wagner Aachen Medical Faculty Institute of Stem Cell Biology Institute of Stem Cell Biology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Helmholtz-Institute for Biomedical Engineering, Medical Faculty of RWTH Aachen University, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospital of RWTH Aachen, 52074 Aachen, Germany

   Institute of Stem Cell Biology, University Hospitl of RWTH Achen, 52074 Achen, Germny