78 Protamine sequence determines nuclear shape in a simplified in vitro system of nuclear remodelling
M. Czernik A B , L. Palazzese B A , A. Sabatucci C , D. Iuso D , S. Curtet D , S. Khochbin D , J. Fulka E , H. Fulka F , E. R. S. Roldan G , M. E. Teves H and P. Loi AA Laboratory of Embryology, Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy
B Institute of Genetics and Animal Biotechnology of the Polish Academy of Sciences, Jastrzebiec, Poland
C Faculty of Bioscience and Technology for Food Agriculture and Environment, Teramo, Italy
D INSERM U823, Institut Albert Bonniot, Université Grenoble Alpes, Grenoble, France
E Institute of Animal Science, Prague, Czech Republic
F Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czech Republic
G Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales 16 (CSIC), Madrid, Spain
H Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, USA
Reproduction, Fertility and Development 35(2) 165-165 https://doi.org/10.1071/RDv35n2Ab78
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
During the final stages of sperm differentiation, the male gamete undergoes a profound modification in shape. One major change involves chromatin compaction and nuclear remodelling. Species differ in the way they achieve this because mature spermatozoa show considerable diversity in nuclear morphology. For example, human sperm have an ellipsoid (straight) nucleus whereas sperm from most rodents have a pyriform (hooked) nucleus. Nuclear shape is believed to result from the action of a microtubular-based platform, the manchette, a transient structure surrounding the elongating head. However, our previous studies revealed that protamines alone could remodel nuclei because human or mouse protamine 1 gene (Prm1) heterologously expressed in somatic cells led to nuclear compaction. Here, we report that the pattern of somatic cell nucleus remodelling varies following the source of Prm1. Human PRM1 compacted fibroblast nuclei in a straight shape, while mouse Prm1 resulted in a hooked nuclear shape in about half of the expressing cells, which are reminiscent of the sperm nuclei of each species. Given that mouse PRM1 has three more cysteines than the human protein, we tested whether differences in intra/inter S-S bonds could account for nuclear shape. When the cysteine residues in mouse PRM1 were progressively depleted by site-directed mutagenesis, and fibroblast nuclei examined after transfection, we found that mouse PRM1 cysteines 15 and 29 were responsible for the hooked nuclear shape. We conclude that Prm1 sequence has an important role in nuclear shaping and that this action is likely modulated by intermolecular disulfide bridges and extensive protamine/DNA interaction.
This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement No. 734434. L.P. and M.C. acknowledge support from the National Science Centre, Poland, through grant No. 2019/35/B/NZ3/02856 (OPUS). MC, LP, PT, and PL were supported by the project “DEMETRA” (MIUR) Department of Excellence 2018–2022. JFJr and HF were supported by GACR 17-08605S. ERSR was supported by the Spanish Ministry of Science, Innovation and Universities grant CGL2016-80577-P.
