DNA organization in human spermatozoa.

Division of Urology, Robert Wood Johnson University Medical School, New Brunswick, New Jersey 08903-0019.
Journal of Andrology (Impact Factor: 1.69). 03/1994; 15(2):139-44. DOI: 10.1002/j.1939-4640.1994.tb00419.x
Source: PubMed

ABSTRACT Previous studies from this laboratory on hamster spermatozoa have demonstrated that rodent sperm DNA is packaged into the sperm nucleus in a specific manner by nuclear structures. The entire genome is organized into DNA loop domains attached at their bases to a sperm nuclear matrix, the skeletal structure of the nucleus. When nuclei are completely decondensed, the nuclear matrix dissipates, and the entire genome remains anchored to a single structure located at the base of the tail, termed the nuclear annulus. Here, we have extended these studies to human sperm nuclei, which were found to be similar to hamster. Human sperm DNA was found to be organized into loop domains attached at their bases to a nuclear matrix. The average size of the human sperm halo of DNA surrounding the extracted sperm nucleus (made up of DNA loop domains) was about 50% smaller than those that have been reported for somatic cells (this corresponds to an approximate loop domain size of 26.8 +/- 2.1 kb). Human sperm DNA also remained anchored to the base of the tail when completely decondensed, indicating the existence of a nuclear annulus-like structure in human spermatozoa; but, unlike the hamster nuclear annulus, the human annulus could not be isolated because of its structural instability when separated from the tail. Using human centromere repeats as a probe for in situ hybridization, we examined the packaging of individual DNA sequences within the sperm nucleus. These studies demonstrate that human sperm DNA is highly organized by nuclear structures.

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    ABSTRACT: Spermatozoa are the smallest and most cyto-differentiated mammalian cells. From a somatic cell-like appearance at the beginning of spermatogenesis, the male germ cell goes through a highly sophisticated process to reach its final organization entirely devoted to its mission which is to deliver the paternal genome to the oocyte. In order to fit the paternal DNA into the tiny spermatozoa head, complete chromatin remodeling is necessary. This review essentially focuses on present knowledge of this mammalian sperm nucleus compaction program. Particular attention is given to most recent advances that concern the specific organization of mammalian sperm chromatin and its potential weaknesses. Emphasis is placed on sperm DNA oxidative damage that may have dramatic consequences including infertility, abnormal embryonic development and the risk of transmission to descendants of an altered paternal genome.
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    ABSTRACT: Objective: To determine whether the period of ejaculatory abstinence (EA) influences the total antioxidant capacity (TAC) of semen or lipid peroxidation (LPO) of sperm membranes. Design: A prospective experimental trial. Setting: Academic medical center for reproductive endocrinology and infertility. Patient(s): Forty men from infertile couples planning intrauterine insemination. Intervention(s): Men provided semen specimens after EA periods of 1 and 4 days. Main Outcome Measure(s): Semen analysis, peroxidase staining, and assays for seminal TAC and sperm membrane LPO, with measures compared between days 1 and 4 within individuals (internal control) using paired t tests. Result(s): The shorter period of EA (1 day vs. 4 days) resulted in statistically significant decreases in semen volume (-24%), sperm density (-28%), and total sperm count (-3.2%). There was a statistically significant increase in TAC with the shorter period of EA (1 day) compared with 4 days of EA. No difference was detected in sperm membrane LPO comparing 1 day of EA and 4 days of EA. Conclusion(s): Higher seminal TAC obtained after a shorter period of EA could diminish oxidative stress-induced sperm damage by a mechanism independent of LPO. Shorter periods of EA may thus improve sperm quality by protecting from reactive oxygen species damage, even though lower numbers of motile sperm are produced after a shorter period of EA. This would be consistent with prior research indicating improved results after intrauterine insemination under these circumstances. (C) 2014 by American Society for Reproductive Medicine.
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    ABSTRACT: Objective Genomic imprinting is the epigenetic change that occurred differentially in the specific genes in spermatozoa and oocyte according to their paternal or maternal origin, thus allowing a monoallelic expression. This review is a critical analysis of the published information relating to the role of the male imprinting on the successful reproduction.Methods We performed a literature search on some of the components that regulate the male genomic imprinting and the possible role on reproductive events such as spermatogenesis, and placental and embryo development.ResultsThe literature analysis allowed us to appreciate structural, genetic and epigenetic changes occurring during the formation of the male gamete that could have an impact on embryo development, mainly in the formation of extraembryonic tissues as the placenta.Conclusions Alterations in the molecular mechanisms involved in the sperm DNA methylation during the spermatogenesis, could induce alterations in the normal pattern of expression required in the fetal-placental components development.
    Actas urologicas españolas 01/2008; 32(10). DOI:10.4321/S0210-48062008001000009 · 1.15 Impact Factor

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