Abstract
Despite their relatively arginine-rich composition, protamines exhibit a high degree of structural variation. Indeed, the primary structure of these histone H1-related sperm nuclear basic proteins (SNBPs) is not random and is the depository of important phylogenetic information. This appears to be the result of their fast rate of evolution driven by positive selection. The way by which the protein variability participates in the transitions that lead to the final highly condensed chromatin organization of spermatozoa at the end of spermiogenesis is not clearly understood. In this paper we focus on the transient chromatin/nucleoplasm patterning that occurs in either a lamellar step or an inversion step during early and mid-spermiogenesis. This takes place in a small subset of protamines in internally fertilizing species of vertebrates, invertebrates and plants. It involves “complex” protamines that are processed, replaced, or undergo side chain modification (such as phosphorylation or disulfide bond formation) during the histone-to-protamine transition. Characteristic features of such patterning, as observed in TEM photomicrographs, include: constancy of the dominant pattern repeat distance λm despite dynamic changes in developmental morphology, bicontinuity of chromatin and nucleoplasm, and chromatin orientation either perpendicular or parallel to the nuclear envelope. This supports the hypothesis that liquid - liquid phase separation by the mechanism of spinodal decomposition may be occurring during spermiogenesis in these species. Spinodal decomposition involves long wave fluctuations of the local concentration with a low energy barrier and thus differs from the mechanism of nucleation and growth that is known to occur during spermiogenesis in internally fertilizing mammals.
Keywords: Protamines, structure, evolution, chromatin/nucleoplasm patterning, lamellae, spermiogenesis, sperm nuclear basic proteins, LAMELLAR, spinodal decomposition, protamine SNBP type, HISTONE H1, ARGININE-RICH PROTAMINES, structural heterogeneity, phylogeny, SPERMATIDS, genome, keratinous protamines, thermal quenching, nucleation, PatchProtamines, structure, evolution, chromatin/nucleoplasm patterning, lamellae, spermiogenesis, sperm nuclear basic proteins, LAMELLAR, spinodal decomposition, protamine SNBP type, HISTONE H1, ARGININE-RICH PROTAMINES, structural heterogeneity, phylogeny, SPERMATIDS, genome, keratinous protamines, thermal quenching, nucleation, Patch
Protein & Peptide Letters
Title: Protamines: Structural Complexity, Evolution and Chromatin Patterning
Volume: 18 Issue: 8
Author(s): Harold E. Kasinsky, Jose Maria Eirin-Lopez and Juan Ausio
Affiliation:
Keywords: Protamines, structure, evolution, chromatin/nucleoplasm patterning, lamellae, spermiogenesis, sperm nuclear basic proteins, LAMELLAR, spinodal decomposition, protamine SNBP type, HISTONE H1, ARGININE-RICH PROTAMINES, structural heterogeneity, phylogeny, SPERMATIDS, genome, keratinous protamines, thermal quenching, nucleation, PatchProtamines, structure, evolution, chromatin/nucleoplasm patterning, lamellae, spermiogenesis, sperm nuclear basic proteins, LAMELLAR, spinodal decomposition, protamine SNBP type, HISTONE H1, ARGININE-RICH PROTAMINES, structural heterogeneity, phylogeny, SPERMATIDS, genome, keratinous protamines, thermal quenching, nucleation, Patch
Abstract: Despite their relatively arginine-rich composition, protamines exhibit a high degree of structural variation. Indeed, the primary structure of these histone H1-related sperm nuclear basic proteins (SNBPs) is not random and is the depository of important phylogenetic information. This appears to be the result of their fast rate of evolution driven by positive selection. The way by which the protein variability participates in the transitions that lead to the final highly condensed chromatin organization of spermatozoa at the end of spermiogenesis is not clearly understood. In this paper we focus on the transient chromatin/nucleoplasm patterning that occurs in either a lamellar step or an inversion step during early and mid-spermiogenesis. This takes place in a small subset of protamines in internally fertilizing species of vertebrates, invertebrates and plants. It involves “complex” protamines that are processed, replaced, or undergo side chain modification (such as phosphorylation or disulfide bond formation) during the histone-to-protamine transition. Characteristic features of such patterning, as observed in TEM photomicrographs, include: constancy of the dominant pattern repeat distance λm despite dynamic changes in developmental morphology, bicontinuity of chromatin and nucleoplasm, and chromatin orientation either perpendicular or parallel to the nuclear envelope. This supports the hypothesis that liquid - liquid phase separation by the mechanism of spinodal decomposition may be occurring during spermiogenesis in these species. Spinodal decomposition involves long wave fluctuations of the local concentration with a low energy barrier and thus differs from the mechanism of nucleation and growth that is known to occur during spermiogenesis in internally fertilizing mammals.
Export Options
About this article
Cite this article as:
E. Kasinsky Harold, Maria Eirin-Lopez Jose and Ausio Juan, Protamines: Structural Complexity, Evolution and Chromatin Patterning, Protein & Peptide Letters 2011; 18 (8) . https://dx.doi.org/10.2174/092986611795713989
DOI https://dx.doi.org/10.2174/092986611795713989 |
Print ISSN 0929-8665 |
Publisher Name Bentham Science Publisher |
Online ISSN 1875-5305 |
![](/images/wayfinder.jpg)
- Author Guidelines
- Bentham Author Support Services (BASS)
- Graphical Abstracts
- Fabricating and Stating False Information
- Research Misconduct
- Post Publication Discussions and Corrections
- Publishing Ethics and Rectitude
- Increase Visibility of Your Article
- Archiving Policies
- Peer Review Workflow
- Order Your Article Before Print
- Promote Your Article
- Manuscript Transfer Facility
- Editorial Policies
- Allegations from Whistleblowers