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Role of Disulfide Bonds on DNA Packaging Forces in Bull Sperm Chromatin
- Source :
- Biophysical Journal. 113:1925-1933
- Publication Year :
- 2017
- Publisher :
- Elsevier BV, 2017.
-
Abstract
- Short arginine-rich proteins called protamines mediate the near crystalline DNA packaging in most vertebrate sperm cells. Protamines are synthesized during spermiogenesis and condense the paternal genome into a transcriptionally inactive state in late-stage spermatids. Protamines from eutherian mammals, including bulls and humans, also contain multiple cysteine residues that form intra- and interprotamine sulfur-sulfur bonds during the final stages of sperm maturation. Although the cross-linked protamine network is known to stabilize the resulting nucleoprotamine structure, little is known about the role of disulfide bonds on DNA condensation in the mammalian sperm. Using small angle x-ray scattering, we show that isolated bull nuclei achieve slightly lower DNA packing densities compared to salmon nuclei despite salmon protamine lacking cysteine residues. Surprisingly, reduction of the intermolecular sulfur-sulfur bonds of bull protamine results in tighter DNA packing. Complete reduction of the intraprotamine disulfide bonds ultimately leads to decondensation, suggesting that disulfide-mediated secondary structure is also critical for proper protamine function. Lastly, comparison of multiple bull collections showed some to have aberrant x-ray scattering profiles consistent with incorrect disulfide bond formation. Together, these observations shed light on the biological functions of disulfide linkages for in vivo DNA packaging in sperm chromatin.
- Subjects :
- Male
0301 basic medicine
endocrine system
Spermiogenesis
Biophysics
DNA condensation
03 medical and health sciences
chemistry.chemical_compound
0302 clinical medicine
Salmon
DNA Packaging
Animals
Amino Acid Sequence
Disulfides
Protamines
Protein secondary structure
Mechanical Phenomena
Nucleic Acids and Genome Biophysics
030219 obstetrics & reproductive medicine
biology
Spermatozoa
Sperm
Protamine
Chromatin
Biomechanical Phenomena
Dithiothreitol
030104 developmental biology
chemistry
Biochemistry
biology.protein
Cattle
DNA
Cysteine
Subjects
Details
- ISSN :
- 00063495
- Volume :
- 113
- Database :
- OpenAIRE
- Journal :
- Biophysical Journal
- Accession number :
- edsair.doi.dedup.....48d1d05b1f99ffef8d8b94afcdd2ece1