OBJECTIVETo identify the effects of overtraining on human sperm DNA.

METHODSMolecular epidemiological investigation of 249 men from different groups (training and non-training) was carried out by using flow cytometer to detect the integrity and damage of in situ DNA of sperm nucleus, and sperm chromatin structure assay was performed.

RESULTSThe average COMPalpha(t) in training group was 11.02% while that in control group was 5.90% (P < 0.01). COMPalpha(t) was significantly correlated with sperm activity (r = 0.41, P < 0.05).

CONCLUSIONOvertraining could induce sperm DNA injury and affect sperm activity, thus to decrease the potentiality of reproduction.

Adult ; Chromatin ; genetics ; metabolism ; DNA Fragmentation ; Exercise ; physiology ; Humans ; Male ; Sperm Motility ; physiology ; Spermatozoa ; cytology ; metabolism

Spermiogenesis is a complex process leading to the formation of motile spermatozoa characterized by a highly stable chromatin compaction that transfers the paternal genome into the oocyte. It is commonly held that these haploid cells are devoid of transcriptional and translational activities and that the transcripts represent remnants of stored mRNAs. Recently, the chromatin organization of mature spermatozoa has been revisited as a double nucleoprotamine-nucleohistone structure possessing less-condensed regions sensitive to nuclease activity, which could be implicated in the expression of genes involved in the early embryo development. The existence of a complex population of mRNAs in human sperm is well-documented, but their role is not yet elucidated. Evidence for a latent transcriptional capacity and/or a potential de novo translation in mature spermatozoa from fertile men are essential for understanding the last steps of sperm maturation, such as capacitation and acrosome reaction. As such, we have documented the relationship between sperm quality and the distribution of sperm RNAs by showing divergent levels of transcripts encoding for proteins involved in either nuclear condensation (protamines 1 and 2) or in capacitation (eNOS and nNOS, c-myc) or in motility and sperm survival (aromatase) between low and high motile sperm issued from the same sample. Therefore, analyzing the profile of mRNAs could be helpful either as a diagnostic tool for evaluating male fertility after spermatogenesis or for prognosis use for fertilization.
Chromatin ; ultrastructure ; Humans ; Male ; Protein Biosynthesis ; RNA, Messenger ; genetics ; Spermatogenesis ; genetics ; physiology ; Spermatozoa ; physiology ; Transcription, Genetic

In eukaryotic cells, histones are packaged into octameric core particles with DNA wrapping around to form nucleosomes, which are the basic units of chromatin (Kornberg and Thomas, 1974). Multicellular organisms utilise chromatin marks to translate one single genome into hundreds of epigenomes for their corresponding cell types. Inheritance of epigenetic status is critical for the maintenance of gene expression profile during mitotic cell divisions (Allis et al., 2006). During S phase, canonical histones are deposited onto DNA in a replication-coupled manner (Allis et al., 2006). To understand how dividing cells overcome the dilution of epigenetic marks after chromatin duplication, DNA replication coupled (RC) nucleosome assembly has been of great interest. In this review, we focus on the potential influence of RC nucleosome assembly processes on the maintenance of epigenetic status.
Animals ; Chromatin Assembly and Disassembly ; genetics ; physiology ; DNA Replication ; Epigenesis, Genetic ; Histones ; chemistry ; physiology ; Humans ; Nucleosomes ; genetics ; physiology ; Protein Structure, Quaternary

Objective: Sperm DNA fragmentation (SDF) is widely used to predict male infertility and the methods of detecting SDF are varied. This study aimed to compare two methods of SDF detection and investigate the correlation between SDF and sperm quality. METHODS: Using sperm chromatin structure assay (SCSA) and sperm chromatin dispersion test (SCD), we detected SDF in 108 semen samples collected in the Center of Reproduction and Genetics of Suzhou Municipal Hospital. We compared the results of the two methods and analyzed the correlations of SDF routine semen parameters, sperm morphology and the age of the patients. RESULTS: A significant consistency was found in the SDF index (DFI) between the two methods (P<0.01). The DFI was correlated negatively with sperm motility, the percentage of progressively motile sperm, and that of morphologically normal sperm (P <0.01), but positively with the teratozoospermia index (P <0.01 in SCSA and P <0.05 in SCD). The DFI measured by SCSA showed a significantly positive correlation with the patients' age (P <0.01), but not that obtained by SCD. CONCLUSIONS The results of both SCSA and SCD play an important role in predicting sperm quality. As a clinical index, the DFI has a predictive value for male infertility. However, the results of different detecting methods vary widely, which calls for further studies on their standardization.
Chromatin ; genetics ; physiology ; DNA Fragmentation ; Humans ; Infertility, Male ; diagnosis ; Male ; Semen ; physiology ; Semen Analysis ; Sperm Motility ; Spermatozoa ; physiology ; ultrastructure

Neural stem cell is presently the research hotspot in neuroscience. Recent progress indicates that epigenetic modulation is closely related to the self-renewal and differentiation of neural stem cell. Epigenetics refer to the study of mitotical/meiotical heritage changes in gene function that cannot be explained by changes in the DNA sequence. Major epigenetic mechanisms include DNA methylation, histone modification, chromatin remodeling, genomic imprinting, and non-coding RNA. In this review, we focus on the new insights into the epigenetic mechanism for neural stem cells fate.
Animals ; Cell Differentiation ; Chromatin Assembly and Disassembly ; DNA Methylation ; Epigenesis, Genetic ; Genomic Imprinting ; Humans ; Neurons ; physiology ; Stem Cells ; physiology

The largest subunit of eukaryotic RNA polymerase II contains a unique domain at its carboxy-terminus, which is referred to as the carboxy-terminal domain (CTD). The CTD is made up of an evolutionarily conserved heptapeptide repeat (YSPTSPS). Over the past decade, there has been increasing attention on the role of the CTD in transcription regulation in the view of mRNA processing and chromatin remodeling. This paper provides a brief overview of the recent progress in the dynamic changes in CTD phosphorylation and its role in integrating multiple nuclear events.
Amino Acid Motifs ; Amino Acid Sequence ; Animals ; Chromatin/*physiology ; Chromatin Assembly and Disassembly ; Conserved Sequence ; Histones/metabolism ; Humans ; Isomerism ; Phosphorylation ; Protein Structure, Tertiary ; RNA Polymerase II/chemistry/*physiology ; RNA, Messenger/metabolism ; Transcription, Genetic

Gene transfer technology is being used to enhance agronomic performance or improve quality traits in a wide variety of crop species. However, it is sometimes severely handicapped by difficulty in obtaining material in which transgene expression is predictable and stable over many generations. Because integration seemed to occur randomly in the plant genome, it was thought that some transgenes would be integrated in a relatively uncondensed, transcriptionally active chromatin environment, while others in a condensed, transcriptionally inert chromatin structure. Nuclear matrix attachment regions (MARs) are defined as DNA sequences that bind preferentially to the proteins of the nuclear matrix. They typically are localized at the borders of gene domains, implicating them in the formation of individual loops of higher order chromatin structure and transcription regulation. When MARs are positioned on either side of a transgene their presence usually results in higher and more stable espression in transgenic plants, most likely by minimizing gene silencing. In this review, we focus mainly on novel findings and our observations concerning the function of MARs in transcription regulation. Our objective is not only to summarize the current data and present several possible models to explain MAR effects on the transcription regulation, but also to point out some open questions involving the utilization of MARs in constructing high efficient expression vectors.
Chromatin ; physiology ; DNA ; metabolism ; Gene Expression Regulation, Plant ; Models, Genetic ; Nuclear Matrix ; metabolism ; Nuclear Proteins ; metabolism ; Transcription, Genetic ; Transgenes ; genetics

AIMTo investigate the prevalence of high levels of sperm DNA damage among men from infertile couples with both normal and abnormal standard semen parameters.

METHODSA total of 350 men from infertile couples were assessed. Standard semen analysis and sperm chromatin structure assay (SCSA) were carried out.

RESULTSNinety-seven men (28% of the whole study group) had a DNA fragmentation index (DFI)> 20%, and 43 men (12%) had a DFI>30%. In the group of men with abnormal semen parameters (n = 224), 35% had a DFI>20%, and 16% had a DFI>30%, whereas these numbers were 15% and 5%, respectively, in the group of men with normal semen parameters (n=126). Men with low sperm motility and abnormal morphology had significantly higher odds ratios (ORs) for having a DFI>20% (4.0 for motility and 1.9 for morphology) and DFI>30% (6.2 for motility and 2.8 for morphology) compared with men with normal sperm motility and morphology.

CONCLUSIONIn almost one-third of unselected men from infertile couples, the DFI exceeded the level of 20% above which, according to previous studies, the in vivo fertility is reduced. A significant proportion of men with otherwise normal semen parameters also had high sperm DNA damage levels. Thus, the SCSA test could add to explaining causes of infertility in cases where semen analysis has not shown any deviation from the norm. We also recommend running the SCSA test to choose the appropriate assisted reproductive technique (ART).

Chromatin ; pathology ; DNA Damage ; Female ; Humans ; Infertility, Male ; epidemiology ; genetics ; physiopathology ; Male ; Prevalence ; Semen ; cytology ; Spermatozoa ; physiology

Enhancing remyelination after injury is of utmost importance for optimizing the recovery of nerve function. While the formation of myelin by Schwann cells (SCs) is critical for the function of the peripheral nervous system, the temporal dynamics and regulatory mechanisms that control the progress of the SC lineage through myelination require further elucidation. Here, using in vitro co-culture models, gene expression profiling of laser capture-microdissected SCs at various stages of myelination, and multilevel bioinformatic analysis, we demonstrated that SCs exhibit three distinct transcriptional characteristics during myelination: the immature, promyelinating, and myelinating states. We showed that suppressor interacting 3a (Sin3A) and 16 other transcription factors and chromatin regulators play important roles in the progress of myelination. Sin3A knockdown in the sciatic nerve or specifically in SCs reduced or delayed the myelination of regenerating axons in a rat crushed sciatic nerve model, while overexpression of Sin3A greatly promoted the remyelination of axons. Further, in vitro experiments revealed that Sin3A silencing inhibited SC migration and differentiation at the promyelination stage and promoted SC proliferation at the immature stage. In addition, SC differentiation and maturation may be regulated by the Sin3A/histone deacetylase2 (HDAC2) complex functionally cooperating with Sox10, as demonstrated by rescue assays. Together, these results complement the recent genome and proteome analyses of SCs during peripheral nerve myelin formation. The results also reveal a key role of Sin3A-dependent chromatin organization in promoting myelinogenic programs and SC differentiation to control peripheral myelination and repair. These findings may inform new treatments for enhancing remyelination and nerve regeneration.
Animals ; Axons ; Chromatin/metabolism* ; Gene Expression Profiling ; Myelin Sheath/metabolism* ; Nerve Regeneration/physiology* ; Rats ; Schwann Cells/metabolism* ; Sciatic Nerve/injuries*

OBJECTIVETo evaluate the role of flow cytometry in semen assessment.

METHODSSemen samples from 104 infertile male patients (as the case group) and 10 fertilized donors (as the control group) were analyzed for the volume of ejaculate and sperm concentration, motility and atypical morphology by computer-assisted semen analysis (CASA), the viability, chromatin structure and mitochondrial membrane potential (MMP) of the sperm stained by SYBR-14/PI, AO and JC-1 respectively, and assessed with flow cytometry. The results were analyzed through SAS software.

RESULTSU tests indicated that the semen from the infertile patients had not only lower concentration (U = 2.51, P = 0.0143), lower motility (U = 3.44, P = 0.001) and higher rate of atypical morphology (U = -5.88, P < 0.0001), but also lower viability (U = 4.72, P < 0.0001), MMP (U = -2.53, P = 0.0309), and chromatin integrity (alpha t: U = -3.82, P = 0.0003; SD alpha t: U = -3.98, P = 0.0001; COMP alpha t: U = -3.57, P = 0.0005). The multiple stepwise regression analysis revealed that sperm motility was positively correlated with sperm membrane integrity (t = 1.66, P = 0.1016), sperm MMP (t = 3.33, P = 0.0014) and sperm acrosome integrity (t = 3.24, P = 0.0019), while sperm MMP was negatively correlated with the rates of sperm neck and tail defects (t = -3.44, P = 0.001).

CONCLUSIONFlow cytometry plays a significant role in the evaluation of the quality of human sperm, and can be adopted as a useful tool in the diagnosis and treatment of male infertility.

Adult ; Case-Control Studies ; Cell Survival ; physiology ; Chromatin ; pathology ; Flow Cytometry ; Humans ; Infertility, Male ; physiopathology ; Male ; Membrane Potentials ; Middle Aged ; Sperm Motility ; Spermatozoa ; abnormalities ; pathology ; physiology