Sperm nuclear basic proteins of Bufo japonicus consist of 2 distinct protamines, whereas those of Xenopus laevis consist of 6 sperm-specific basic proteins (SP1-6) in addition to H3, H4 and smaller amounts of H2A and H2B. Cloning of pertinent cDNAs and partial amino acid sequence studies suggested that these 6 sperm-specific proteins of Xenopus are encoded by 3 distinct genes. Despite differenc...

We report the isolation and characterization of a new nuclear structure from spermatozoa of the golden Syrian hamster which we term the nuclear annulus. The nuclear annul us was located at the implantation fossa, the point at which the tail is joined to the sperm head, inside the nucleus adjacent to the inner nuclear envelope. Extraction of sperm nuclei with 2 M NaC1 and 10 mM dithiothreitol ca...

Protamines are expressed in the spermatid nucleus and allow denser packaging of DNA compared with histones. Disruption of the coding sequence of one allele of either protamine 1 (Prm1) or Prm2 results in failure to produce offspring, although sperm with disrupted Prm1 or Prm2 alleles are produced. Here, we produced Prm1-deficient female chimeric mice carrying Prm1-deficient oocytes. These mice ...

H uman sperm chromatin, and the sperm of most mammals, undergoes extensive remodeling during spermiogenesis during which 85%–95% of the histones are removed and replaced with protamines. The replacement of most histones with protamines facilitates a tighter packaging of the chromatin that is necessary for normal sperm function, and may help protect sperm DNA from damage during transport. An int...

Several studies have investigated the association between polymorphisms in protamine 1 and 2 genes and male infertility risk, with inconsistent results to date. This meta-analysis based on the 13 published case-control studies, including 7350 cases and 6167 controls, was performed to further establish the potential association between the 6 common single nucleotide polymorphisms (rs35576928, rs...

Epigenetic information can be passed on from one generation to another via DNA methylation, histone modifications, and changes in small RNAs, a process called epigenetic memory. During a mammal's lifecycle epigenetic reprogramming, or the resetting of most epigenetic marks, occurs twice. The first instance of reprogramming occurs in primordial germ cells and the second occurs following fertiliz...

In most animals, the extreme compaction of sperm DNA is achieved after the massive replacement of histones with sperm nuclear basic proteins (SNBPs), such as protamines. In some species, the ultracompact sperm chromatin is stabilized by a network of disulfide bonds connecting cysteine residues present in SNBPs. Studies in mammals have established that the reduction of these disulfide crosslinks...

Very few data are available concerning the amino acid content of mammalian sperm. The early work by Kossel (1) on the protamines of fish sperm and on the histones was primarily concerned with an attempt to elucidate the structure of the basic proteins. The basic proteins are, in general, characterized by a high arginine content. Zittle and O’Dell (2) have determined the methionine content of wh...