The association of stromal antigen 3 (STAG3) sequence variations with spermatogenic impairment in the male Korean population

Genetic variants underlying spermatogenic arrests in men with non-obstructive azoospermia

Spermatogenic arrest is a severe form of non-obstructive azoospermia (NOA), which occurs in 10-15% of infertile men. Interruption in spermatogenic progression at premeiotic, meiotic, or postmeiotic stage can lead to arrest in men with NOA. Recent studies have intensively focused on defining genetic variants underlying these spermatogenic arrests by making genome/exome sequencing. A number of variants were discovered in the genes involving in mitosis, meiosis, germline differentiation and other basic cellular events. Herein, defined variants in NOA cases with spermatogenic arrests and created knockout mouse models for the related genes are comprehensively reviewed. Also, importance of gene panel-based screening for NOA cases was discussed. Screening common variants in these infertile men with spermatogenic arrests may contribute to elucidating the molecular background and designing novel treatment strategies.

Transcriptome sequencing reveals the effects of circRNA on testicular development and spermatogenesis in Qianbei Ma goats

Circular RNAs (circRNAs) play an important role in regulating the mammalian reproductive system, especially testicular development and spermatogenesis. However, their functions in testicular development and spermatogenesis in the Qianbei Ma goat, the Guizhou endemic breed are still unclear. In this study, tissue sectioning and circRNAs transcriptome analysis were conducted to compare the changes of morphology and circular RNAs gene expression profile at four different developmental stages (0Y, 0-month-old; 6Y, 6-month-old; 12Y, 12-month-old; 18Y, 18-month-old). The results showed that the circumferences and area of the seminiferous tubule gradually increased with age, and the lumen of the seminiferous tubule in the testis differentiated significantly. 12,784 circRNAs were detected from testicular tissues at four different developmental stages by RNA sequencing, and 8,140 DEcircRNAs (differentially expressed circRNAs) were found in 0Y vs. 6Y, 6Y vs. 12Y, 12Y vs. 18Y and 0Y vs. 18Y, 0Y vs. 12Y, 6Y vs. 18Y Functional enrichment analysis of the source genes showed that they were mainly enriched in testicular development and spermatogenesis. In addition, the miRNAs and mRNAs associated with DECircRNAs in 6 control groups were predicted by bioinformatics, and 81 highly expressed DECircRNAs and their associated miRNAs and mRNAs were selected to construct the ceRNA network. Through functional enrichment analysis of the target genes of circRNAs in the network, some candidate circRNAs related to testicular development and spermatogenesis were obtained. Such as circRNA_07172, circRNA_04859, circRNA_07832, circRNA_00032 and circRNA_07510. These results will help to reveal the mechanism of circRNAs in testicular development and spermatogenesis, and also provide some guidance for goat reproduction.

Fluorescent Polymerase Chain Reaction Nanokit for the Detection of DNA Sequence in Single Living Cells

Here, a fluorescent polymerase chain reaction (PCR) nanokit is established to detect the specific DNA sequence in a single living cell. Different from well-developed protocols to load cell-permeable probes into single cell for recognition, the DNA sequence in a cellular nucleus is sorted into a nanopipette in our strategy. The target DNA sequence is reacted with the PCR kit components in the nanopipette to complete a PCR amplification reaction. SYBR Green prefilled in the nanopipette is intercalated into double-stranded DNA to induce fluorescence emission for real-time detection down to a single copy. An obvious increase in the fluorescence is observed that validates the detection of the target DNA sequence in single living cells. The established real-time fluorescent PCR nanokit could adapt the PCR kit for single cell analysis and thus offers an alternatively general and highly sensitive strategy for the detection of specific DNA sequences in single living cells.

The gene regulatory role of non-coding RNAs in non-obstructive azoospermia

Non-coding RNAs are classified as small non-coding RNAs, long non-coding RNAs and circular RNAs, which are involved in a variety of biological processes, including cell differentiation, proliferation, apoptosis and pathological conditions of various diseases. Many studies have shown that non-coding RNAs are related to spermatogenesis, maturation, apoptosis, function, etc. In addition, the expression of non-coding RNAs in testicular tissue and semen of patients with non-obstructive azoospermia was different. However, the role of non-coding RNAs in the pathogenesis of non-obstructive azoospermia has not been fully elucidated, and the role of non-coding RNAs in non-obstructive azoospermia is rarely reviewed. Here we summarize the research progress of non-coding RNAs in the pathogenesis of non-obstructive azoospermia.

Analysis of STAG3 variants in Chinese non-obstructive azoospermia patients with germ cell maturation arrest

STAG3 is essential for male meiosis and testis of male Stag3^-/- mice shows the histopathological type of germ cell maturation arrest (MA). Whether variants of the STAG3 gene exist in Chinese idiopathic non-obstructive azoospermia (NOA) patients needs to be determined. We recruited 58 Chinese NOA men with MA who underwent testis biopsy and 192 fertile men as the control group. The 34 exons of the STAG3 gene were amplified using polymerase chain reaction (PCR) and sequenced. We identified eight novel single nucleotide polymorphisms (SNPs), including two missense SNPs (c.433T > C in exon2 and c.553A > G in exon3), three synonymous SNPs (c.539G > A, c.569C > T in exon3, and c.1176C > G in exon8), and three SNPs in introns. The allele and genotype frequencies of the novel and other SNPs have no significant differences between two groups. Our results indicated that variants in the coding sequence of the STAG3 gene were uncommon in NOA patients with MA in Chinese population. Future studies in large cohorts of different ethnic populations will be needed to determine the association between the STAG3 gene and NOA.

Characterization of the major human STAG3 variants using some proteomics and bioinformatics assays

Background

STAG3 is the meiotic component of cohesin and a member of the Cancer Testis Antigen (CTA) family. This gene has been found to be overexpressed in many types of cancer, and recently, its variants have been implicated in other disorders and many human diseases. Therefore, this study aimed to analyze the major variants of STAG3. Western blot (WB) and immunoprecipitation (IP) assays were performed using two different anti-STAG3 antibodies that targeted the relevant protein in MCF-7, T-47D, MDA-MB-468, and MDA-MB-231 breast cancer cells with Jurkat and MCF-10A cells as positive and negative controls, respectively. In silico analyses were searched to study the major isoforms.

Results

WB and IP assays revealed two abundant polypeptides < 191 kDa and ~ 75 kDa in size. Specific bioinformatics tools successfully determined the three-dimensional (3-D) structure, the subcellular localization, and the secondary structures of the isoforms. Furthermore, some of the physicochemical properties of the STAG3 proteins were also determined.

Conclusions

The results of this study revealed the power of applying the biological techniques (WB and IP) with the bioinformatics assays and the possibility of their exploitation in understanding diseased genes. Exploring the major variants of STAG3 at the protein level could help decipher some disorders associated with their occurrence, along with designing drugs effective at least for some relevant diseases.

Genetic Landscape of Nonobstructive Azoospermia and New Perspectives for the Clinic

Nonobstructive azoospermia (NOA) represents the most severe expression of male infertility, involving around 1% of the male population and 10% of infertile men. This condition is characterised by the inability of the testis to produce sperm cells, and it is considered to have an important genetic component. During the last two decades, different genetic anomalies, including microdeletions of the Y chromosome, karyotype defects, and missense mutations in genes involved in the reproductive function, have been described as the primary cause of NOA in many infertile men. However, these alterations only explain around 25% of azoospermic cases, with the remaining patients showing an idiopathic origin. Recent studies clearly suggest that the so-called idiopathic NOA has a complex aetiology with a polygenic inheritance, which may alter the spermatogenic process. Although we are far from a complete understanding of the molecular mechanisms underlying NOA, the use of the new technologies for genetic analysis has enabled a considerable increase in knowledge during the last years. In this review, we will provide a comprehensive and updated overview of the genetic basis of NOA, with a special focus on the possible application of the recent insights in clinical practice.