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Low sperm motility is a significant contributor to male infertility. beta-defensins have been implicated in host defence and the acquisition of sperm motility; however, the regulatory mechanisms governing their gene expression patterns and functions remain poorly understood. In this study, we performed single-cell RNA and spatial transcriptome sequencing to investigate the cellular composition of testicular and epididymal tissues and examined their gene expression characteristics. In the epididymis, we found that epididymal epithelial cells display a region specificity of gene expression in different epididymal segments, including the beta-defensin family genes. In particular, Defb15, Defb18, Defb20, Defb25 and Defb48 are specific to the caput; Defb22, Defb23 and Defb26 to the corpus; Defb2 and Defb9 to the cauda of the epididymis. To confirm this, we performed mRNA fluorescence in situ hybridisation (FISH) targeting certain exon region of beta-defensin genes, and found some of their expression matched the sequencing results and displayed a close connection with epididimosome marker gene Cd63. In addition, we paid attention to the Sertoli cells and Leydig cells in the testis, along with fibroblasts and smooth muscle cells in the epididymis, by demonstrating their gene expression profile and spatial information. Our study provides a single-cell and spatial landscape for analysing the gene expression characteristics of testicular and epididymal environments and has important implications for the study of spermatogenesis and sperm maturation. [ABSTRACT FROM AUTHOR]

Simple Summary: Abnormal expression of the HSF2 gene was shown to be associated with male sterility. Here, we found that HSF2 was highly expressed in the testes of the cattle-yak, especially in adult cattle-yak. However, the expression of HSF2 was significantly lower in the cattle-yak compared to cattle and yak. In addition, the methylation level of the promoter region was significantly higher in cattle-yak compared to yak. We therefore suggest that male cattle-yak sterility may be associated with methylation of the HSF2 gene in testes tissues. This study provides theoretical support for further understanding of male cattle-yak sterility. Aberrant expression of the heat shock proteins and factors was revealed to be closely associated with male reproduction. Heat shock factor 2 (HSF2) is a transcription factor that is involved in the regulation of diverse developmental pathways. However, the role and the corresponding molecular mechanism of HSF2 in male cattle-yak sterility are still poorly understood. Therefore, the aim of this study was to obtain the sequence and the biological information of the cattle-yak HSF2 gene and to investigate the spatiotemporal expression profiles of the locus during the development of cattle-yak testes. Additionally, the differential expression was analyzed between the cattle-yak and the yak, and the methylation of corresponding promoter regions was compared. Our results showed an additional 54 bp fragment and a missense mutation (lysine to glutamic acid) were presented in the cattle-yak HSF2 gene, which correlated with enriched expression in testicular tissue. In addition, the expression of the HSF2 gene showed dynamic changes during the growth of the testes, reaching a peak in adulthood. The IHC indicated that HSF2 protein was primarily located in spermatocytes (PS), spermatogonia (SP), and Sertoli cells (SC) in cattle-yak testes, compared with the corresponding cells of cattle and the yak. Furthermore, bisulfite-sequencing PCR (BSP) revealed that the methylated CpG sites in the promoter region of the cattle-yak HSF2 were more numerous than in the yak counterpart, which suggests hypermethylation of this region in the cattle-yak. Taken together, the low expression abundance and hypermethylation of HSF2 may underpin the obstruction of spermatogenesis, which leads to male cattle-yak infertility. Our study provided a basic guideline for the HSF2 gene in male reproduction and a new insight into the mechanisms of male cattle-yak sterility. [ABSTRACT FROM AUTHOR]

Objectives: Oxidative stress and disruption of energy metabolism in the reproductive system, especially sperm, play a significant role in diabetes-related infertility. Zataria multiflora Boissis (ZMB), a medicinal plant containing various bioactive compounds, may have efficacy in treating metabolic diseases and reproductive disorders. Therefore, the aim of this study was to investigate the effects of different doses of ZMB extract on diabetes-induced reproductive dysfunction by assessing oxidative damage and the gene expression of insulin receptor substrate (IRS) and pyruvate kinase (PK) in male rats' sperm. Methods: Sixty adult male Wistar rats were randomly divided into six groups; control (C), diabetes (D), and diabetic animals treated with glibenclamide (G, 50 mg/kg) and thyme extract (T100, T200, and T400). Diabetes was induced by intraperitoneal injection of Streptozotocin (STZ) (50 mg/kg). Insulin, glucose, oxidative and pro-inflammatory markers in the serum, and gene expressions of IRS, and PK were measured in the stored sperms in the epididymis. Changes in the process of spermatogenesis were assessed through the histological evaluation of the testis. Gas chromatography–mass spectrometry (GC–MS) was used to analyze the quantity and quality of thyme extract. Key findings: The study results indicated that body weight, food intake, and sperm parameters significantly improved in a dose-dependent manner in the T200 group compared to the other groups. Additionally, in the same group, pro-inflammatory biomarkers, DNA fragmentation, and MDA levels decreased, while the levels of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) enzymes in the stored epididymal sperm significantly improved compared to the other groups. The expression of IRS and PK, along with the mean counts of spermatogenesis cell lines (especially Sertoli cells), significantly increased in the T200 group. Summary: In conclusion, thymol appears to alleviate diabetes-induced reproductive dysfunction by inhibiting oxidative damage, improving the metabolic state, and upregulating the expression of IRS and PK genes in the sperm of male rats. Graphical Abstract [ABSTRACT FROM AUTHOR]

Background: Disorders/differences of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal, or anatomical sex is atypical. With overlapping phenotypes and multiple genes involved, poor diagnostic yields are achieved for many of these conditions. The current DSD diagnostic regimen can be augmented by investigating transcriptome/proteome in vivo, but it is hampered by the unavailability of affected gonadal tissue at the relevant developmental stage. We try to mitigate this limitation by reprogramming readily available skin tissue-derived dermal fibroblasts into Sertoli cells (SC), which could then be deployed for different diagnostic strategies. SCs form the target cell type of choice because they act like an organizing center of embryonic gonadal development and many DSD arise when these developmental processes go awry. Methods: We employed a computational predictive algorithm for cell conversions called Mogrify to predict the transcription factors (TFs) required for direct reprogramming of human dermal fibroblasts into SCs. We established trans-differentiation culture conditions where stable transgenic expression of these TFs was achieved in 46, XY adult dermal fibroblasts using lentiviral vectors. The resulting Sertoli like cells (SLCs) were validated for SC phenotype using several approaches. Results: SLCs exhibited Sertoli-like morphological and cellular properties as revealed by morphometry and xCelligence cell behavior assays. They also showed Sertoli-specific expression of molecular markers such as SOX9, PTGDS, BMP4, or DMRT1 as revealed by IF imaging, RNAseq and qPCR. The SLC transcriptome shared about two thirds of its differentially expressed genes with a human adult SC transcriptome and expressed markers typical of embryonic SCs. Notably, SLCs lacked expression of most markers of other gonadal cell types such as Leydig, germ, peritubular myoid or granulosa cells. Conclusions: The trans-differentiation method was applied to a variety of commercially available 46, XY fibroblasts derived from patients with DSD and to a 46, XX cell line. The DSD SLCs displayed altered levels of trans-differentiation in comparison to normal 46, XY-derived SLCs, thus showcasing the robustness of this new trans-differentiation model. Future applications could include using the SLCs to improve definitive diagnosis of DSD in patients with variants of unknown significance. Highlights: Disorders/differences of sex development (DSD) have low diagnostic rates. Validation of variants of unknown significance and discovery of developmental pathways can be improved by utilizing gonadal tissue/cell for genomic and transcriptomic analysis. As these cells are not readily accessible, we have developed a novel method for trans-differentiating 46, XY dermal fibroblasts into Sertoli-like cells (SLC). Our trans-differentiation method can produce SLCs from dermal fibroblasts belonging to a variety of 46,XY DSDs, thus showing its robustness. This method can aid as a tool for precision medicine towards diagnosing DSD. Plain language summary: Individuals with disorders/differences of sex development (DSD) frequently do not get a specific genetic diagnostic. A limitation in the field is that the relevant cell types that would be needed to study the molecular events occurring at the time of onset of many DSD are found in the embryonic gonad. This, of course, is not accessible for research or diagnostic purposes. We set out to develop a method for directly transforming more accessible cells, from adult skin, into the cells known to organize the male gonad in the embryo, Sertoli cells. A combination of unique transcription factors was stably integrated into skin fibroblasts, and culture under appropriate conditions allowed differentiation into Sertoli-like cells (SLC), but not other gonadal cell types. The SLCs recapitulated known patterns of gene expression, shape, and behavior of Sertoli cells. The method was also tested on commercially available fibroblasts from a variety of DSD genetic backgrounds. The resulting cells exhibited condition-specific behavior (gene expression, adhesion to substrate, division rate...). This method provides a new tool to study molecular events occurring at the time of onset of DSD in the embryonic gonad, and the impact of patient-specific mutations on those. It could allow identification of new developmental pathways (and, thus, new candidate genes for DSD), as well as a provide models to validate the impact of variants of unknown significance, or to test approaches to correct the genetic anomaly in patient cells. [ABSTRACT FROM AUTHOR]

• Chlorophytum borivilianum Santapau & R.R.Fern. (C. borivillianum) used for the treatment of male sexual dysfunction and oligospermia. • Ethanolic extract and saponin enriched n-butanol fraction was evaluated to evolve the underlying biochemical mechanism for spermatogenic potential of C. borivilianum. • Ethanolic extract and saponin enriched n-butanol fraction evaluated to alter fold shift in the mRNA expression of the StAR and 3β-HSD enzymes. • Saponin enriched n-butanol fraction might have interacted with CREB and additionally stimulated LH receptors to amplify the expression of 3β-HSD and StAR mRNA. Traditional applications of the roots of Chlorophytum borivilianum Santapau & R.R.Fern. include spermatogenic potential. Using rats as test subjects, the potential of alcoholic extract (AE-SM) and n-Butanol fraction (NB-SM), which is rich in saponin, to alter the levels of testicular testosterone and cholesterol as well as mRNA expression of the 3β-Hydroxy-∆5- steroid dehydrogenase (3β-HSD) and Acute Steroid Regulatory Protein (StAR) were determined. Histological analyses of testicular tissues were performed, and the quantity of sperm in the seminal fluid was measured. The testosterone concentration increased in AE-SM and NB-SM in a dose-dependent and statistically significant manner. In-vivo mRNA expression of the StAR and 3β-HSD enzymes was also enhanced by the test samples. When compared to control animals, AE-SM and NB-SM increased testicular testosterone by 11.46 and 12.98 fold, respectively, while the extract and fractions revealed a 5.72 and 7.70 fold alteration in StAR mRNA expression. In testicular tissues, AE-SM and NB-SM increased 3β-HSD activity by 4.98 and 9.05 fold, respectively, while changing the expression of the 3β-HSD mRNA by 6.46 and 15.54 factor, respectively. The fluid sampled from the caudal region of the AE-SM and NB-SM indicated an increased sperm concentration, and histological examinations revealed dense Sertoli cell cytoplasm and an increase in the number of sperms in the luminal part of the seminiferous tubules. The components of AE-SM and NB-SM might stimulated testosterone biosynthesis in-vivo by modifying mRNA expression of selected steroidogenic enzymes. By modifying the mRNA expression of the StAR and 3β-HSD, AE-SM and NB-SM can raise the level of testosterone in testicular tissues. As evidenced by an elevated sperm concentration discovered within the seminiferous fluid and histological studies, overexpression of steroidogenic enzymes increased testicular testosterone levels and may have stimulated the spermatogenesis process.Saponin enriched n-butanol fraction might have interacted with CREB and additionally stimulated LH receptors to elevate the StAR and 3β-HSD mRNA expression. [ABSTRACT FROM AUTHOR]

The objective was to determine effects of dietary supplementation of barley sprouts (BS) and/or d -aspartic acid (DA) on the reproductive potential of aged broiler roosters. Birds (n = 32, 50 wk old) were randomly allocated to receive dietary supplements of BS powder (2 % of basal diet), and DA (200 mg/kg BW), both, or neither, for 12 wk. Roosters were housed individually, with 14-h light/10-h dark, ad libitum feed and water, and euthanized after 12 wk. Mean (±SEM) total phenolic compounds and IC 50 in methanol extract of sprouted barley were 302.8 ± 10.9 mg GAE/g and 600.8 ± 50.5 mg TE per 100 g, respectively. In weekly semen collections, sperm total and progressive motility, plasma membrane integrity, sperm concentration, and sperm production were higher (P < 0.05) in both the DA + BS and BS groups compared to the Control, but sperm abnormalities were unaffected. Feeding DA increased right, left, and combined testicular weights (P < 0.05, P < 0.05, and P < 0.01, respectively) and, the testicular index (P = 0.01). Feeding BS increased seminiferous tubule diameter (P < 0.01), whereas BS + DA increased seminiferous epithelium thickness (P < 0.01). There were more spermatogonia (P < 0.01) and Leydig cells (P < 0.05) in BS-fed roosters but Sertoli cells were highest in BS + DA (P < 0.01). Serum MDA concentrations were lowest in BS (P < 0.01), whereas serum testosterone and LH were highest in DA (P < 0.05) and BS + DA (P < 0.01), respectively. Feeding BS reduced serum total cholesterol (P < 0.05) and increased serum HDL-cholesterol (P < 0.01), with decreases in serum LDL (P < 0.01) and the LDL/HDL ratio (P < 0.01) for BS + DA compared to Control. Relative expression of glutathione peroxidase mRNA was increased by BS (P < 0.01) or DA (P < 0.05), whereas relative mRNA expression of SOD was highest in BA (P < 0.01). Control roosters were highest for both BAX (P < 0.01) and the relative expression of the BAX/BCL-2 ratio (P < 0.01), whereas BS + DA increased BCL-2 (P < 0.05). In conclusion, feeding BS, and/or DA significantly improved reproductive potential in aged broiler roosters. • Objective was to improve reproductive performance of aged broiler roosters. • Dietary supplementation of barley sprouts (BS) extract and d -aspartic acid (DA). • In the serum, BS and DA enhanced antioxidant status, LH and testosterone, and lipids. • In the testes, BS and DA reduced apoptosis and improved histology. [ABSTRACT FROM AUTHOR]

Background: The absence of expression of the Y-chromosome linked testis-determining gene SRY in early supporting gonadal cells (ESGC) leads bipotential gonads into ovarian development. However, genetic variants in NR2F2, encoding three isoforms of the transcription factor COUP-TFII, represent a novel cause of SRY-negative 46,XX testicular/ovotesticular differences of sex development (T/OT-DSD). Thus, we hypothesized that COUP-TFII is part of the ovarian developmental network. COUP-TFII is known to be expressed in interstitial/mesenchymal cells giving rise to steroidogenic cells in fetal gonads, however its expression and function in ESGCs have yet to be explored. Results: By differentiating induced pluripotent stem cells into bipotential gonad-like cells in vitro and by analyzing single cell RNA-sequencing datasets of human fetal gonads, we identified that NR2F2 expression is highly upregulated during bipotential gonad development along with markers of bipotential state. NR2F2 expression was detected in early cell populations that precede the steroidogenic cell emergence and that retain a multipotent state in the undifferentiated gonad. The ESGCs differentiating into fetal Sertoli cells lost NR2F2 expression, whereas pre-granulosa cells remained NR2F2-positive. When examining the NR2F2 transcript variants individually, we demonstrated that the canonical isoform A, disrupted by frameshift variants previously reported in 46,XX T/OT-DSD patients, is nearly 1000-fold more highly expressed than other isoforms in bipotential gonad-like cells. To investigate the genetic network under COUP-TFII regulation in human gonadal cell context, we generated a NR2F2 knockout (KO) in the human granulosa-like cell line COV434 and studied NR2F2-KO COV434 cell transcriptome. NR2F2 ablation downregulated markers of ESGC and pre-granulosa cells. NR2F2-KO COV434 cells lost the enrichment for female-supporting gonadal progenitor and acquired gene signatures more similar to gonadal interstitial cells. Conclusions: Our findings suggest that COUP-TFII has a role in maintaining a multipotent state necessary for commitment to the ovarian development. We propose that COUP-TFII regulates cell fate during gonad development and impairment of its function may disrupt the transcriptional plasticity of ESGCs. During early gonad development, disruption of ESGC plasticity may drive them into commitment to the testicular pathway, as observed in 46,XX OT-DSD patients with NR2F2 haploinsufficiency. [ABSTRACT FROM AUTHOR]

Lambda light chains (λ‐LCs) are frequently responsible for triggering the activation of inflammatory factors in autoimmune disorders, and an increase in their levels will cause various pathological changes in serum. The aim of this study was to determine the histological differences between the epididymis and testis of normal and cryptorchid Bactrian camels and the differences in λ‐LC expression in the epididymis and testis of normal and cryptorchid Bactrian camels. Haematoxylin and eosin (H&E) staining was used to examine the pathological changes in cryptorchidism. The gene and protein levels of λ‐LC were determined using RT‐qPCR and western blot. The distribution of λ‐LCs was assessed by immunohistochemistry and immunofluorescence. Compared with that in normal Bactrian camels, the diameter of the epididymal lumen and the thickness of the epithelium were decreased in the epididymis of cryptorchidic animals. Additionally, no sperm was detected in the cavity of the cryptorchidic epididymis. Meanwhile, the expression of λ‐LC was significantly increased in the cryptorchidic epididymis at both the mRNA and protein levels (p <.05). The highest protein expression of λ‐LC was found in epididymal epithelial halo cells and testicular Sertoli cells. These findings suggested that the structural changes observed in the epididymal epithelium of cryptorchidic camels affect its secretory and absorptive functions. Additionally, the high level of λ‐LC expression recorded in halo cells suggested that these cells play an important role in epithelial immunity in cryptorchidic Bactrian camels. Furthermore, the high λ‐LC expression levels detected in normal testicular Sertoli cells indicated that λ‐LCs may be involved in spermatogenesis. The results of this study provide clues for an in‐depth study of immunological sterility in cryptorchidic Bactrian camels. [ABSTRACT FROM AUTHOR]

Sertoli cells (SC) are a type of important cells in the testes, which can provide transport proteins, regulatory proteins, growth factors, and other cytokines for the spermatogenic process. They participate in the regulation of the maturation and differentiation of spermatogenic cells and play an important supporting role in the migration, proliferation, and differentiation of germ cells at all levels in the testes. Previous studies found differential expression of LINC9137, miR-140-3p, and Sodium/Potassium Transporting ATPase Interacting 3 ( NKAIN3 ) genesin high and low sperm motility goose testicular tissues. This study investigated the effects of the LINC9137-miR-140-3p- NKAIN3 signal axis on the proliferation and apoptosis of goose testicular sertoli cells at the cellular level, respectively. The results showed that through acridine orange staining, oil red O staining, Alkaline phosphatase (AKP) staining, and RT qPCR assay, it was comprehensively identified that the cultured testicular sertoli cells were purified in vitro. Through the dual luciferase activity detection test, it was found that LINC9137 has a targeted binding site with miR-140-3p and NKAIN3. In addition, this study found that overexpression of miR-140-3p significantly inhibited the expression of LINC9137 and NKAIN3 in sertoli cells, and their expression was significantly increased when miR-140-3p was interfered with. By measuring cell proliferation activity and apoptosis related gene expression, it was found that overexpression of LINC9137 decreased cell proliferation activity (P > 0.05), while the expression level of apoptosis factor Bcl2 Associated X Protein ( Bax )/B-cell lymphoma-2 ( Bcl2 ) increased (P > 0.05). On the contrary, when interfering with LINC9137, the cell proliferation activity of sertoli cells was significantly increased (P < 0.01), and the expression level of apoptosis factor Bax / Bcl2 was significantly reduced (P < 0.05); The effect of miR-140-3p on the proliferation and apoptosis of sertoli cells is opposite to that of LINC9137. Meanwhile, this study co transfected overexpressed LINC9137 and miR-140-3p plasmids into sertoli cells, and found that the effect of LINC9137 overexpression on supporting cell proliferation was weakened by miR-140-3p. This study elucidates the role and function of the LINC9137 miR-140-3p- NKAIN3 signaling axis in the development of goose testes and spermatogenesis, establishes a regulatory network related to spermatogenesis, and provides a theoretical basis for studying the genetic regulation of goose spermatogenesis. [ABSTRACT FROM AUTHOR]

The generally undesired effects of exocannabinoids on male reproduction include alterations in testicular cell proliferation and function, as well as apoptosis induction. However, this paradigm has been challenged by the ability of endocannabinoids to regulate reproductive function. The present study addresses these paradoxical facts by investigating the effects of the endocannabinoid 2-arachidonoyl glycerol (2-AG) on mouse Sertoli cells' survival and apoptosis, with a mechanistic insight into Sertoli cell-based growth factors' production. The Mus musculus Sertoli cell line (TM4) was exposed to different concentrations of 2-AG, and cell viability was evaluated using MTT assay. Growth factors' gene and protein expressions were analyzed through RT-PCR and western blotting. 2-AG concentration dependently increased TM4 viability, with a slight increase starting at 0.0001 µM, a peak of 190% of the control level at 1 µM, and a decrease at 3 µM. Moreover, 2-AG paradoxically altered mRNA expression of caspase-3 and growth factors. Caspase-3 mRNA expression was down-regulated, and growth factors mRNA and protein expression were up-regulated when using a low concentration of 2-AG (1 μM). Opposite effects were observed by a higher concentration of 2-AG (3 μM). These paradoxical effects of 2-AG can be explained through the concept of hormesis. The results indicate the pivotal role of 2-AG in mediating Sertoli cell viability and apoptosis, at least in part, through altering growth factors secretion. Furthermore, they suggest the involvement of endocannabinoids in Sertoli cell-based physiological and pathological conditions and reflect the ability of abnormally elevated 2-AG to mimic the actions of exocannabinoids in reproductive dysfunction. • TM4 Sertoli cell viability increased upon exposure to 1 μM of 2-AG. • Caspase-3 expression decreased in TM4 cells exposed to 1 μM of 2-AG. • Exposure to 1 μM of 2-AG increased growth factors mRNA and protein levels. • 3 μM of 2-AG had contrasting effects. • Paradoxical effects of 2-AG can be explained through the concept of hormesis. [ABSTRACT FROM AUTHOR]

Long noncoding RNAs (lncRNAs) are transcribed in complex, overlapping, sense- and antisense orientations from intronic and intergenic regions of mammalian genomes. Transcription of genome in mammalian testis is more widespread compared to other organs. LncRNAs are involved in gene expression, chromatin regulation, mRNA stability and translation of proteins during diverse cellular functions. We report molecular cloning of two novel lncRNAs (mLINC-RBE and mLINC-RSAS) and their expression by RT-PCR as well as cellular localization by RNA in-situ hybridization in the mouse testes. mLINC-RBE is an intergenic lncRNA from chromosome 4, with 16.96 % repeat sequences, expressed as a sense transcript with piRNA sequences and its expression is localized into primary spermatocytes. mLINC-RSAS is an intergenic lncRNA from chromosome 2, with 49.7 % repeat sequences, expressed as both sense- and antisense transcripts with miRNA sequences and its expression is localized into different cell types, such as Sertoli cells, primary spermatocytes and round spermatids. The lncRNAs also contain sequences for some short peptides (micropeptides). This suggests that these two repeat sequence containing, intergenic genomic sense- and antisense transcripts expressed as lncRNAs with piRNAs, miRNAs, and showing cell-type specific, differential expression may regulate important functions in mammalian testes. Such functions may be regulated by RNA structures, RNA processing and RNA-protein complexes. [Display omitted] [ABSTRACT FROM AUTHOR]

Long noncoding RNAs (lncRNAs) are transcribed in complex, overlapping, sense- and antisense orientations from intronic and intergenic regions of mammalian genomes. Transcription of genome in mammalian testis is more widespread compared to other organs. LncRNAs are involved in gene expression, chromatin regulation, mRNA stability and translation of proteins during diverse cellular functions. We report molecular cloning of two novel lncRNAs (mLINC-RBE and mLINC-RSAS) and their expression by RT-PCR as well as cellular localization by RNA in-situ hybridization in the mouse testes. mLINC-RBE is an intergenic lncRNA from chromosome 4, with 16.96 % repeat sequences, expressed as a sense transcript with piRNA sequences and its expression is localized into primary spermatocytes. mLINC-RSAS is an intergenic lncRNA from chromosome 2, with 49.7 % repeat sequences, expressed as both sense- and antisense transcripts with miRNA sequences and its expression is localized into different cell types, such as Sertoli cells, primary spermatocytes and round spermatids. The lncRNAs also contain sequences for some short peptides (micropeptides). This suggests that these two repeat sequence containing, intergenic genomic sense- and antisense transcripts expressed as lncRNAs with piRNAs, miRNAs, and showing cell-type specific, differential expression may regulate important functions in mammalian testes. Such functions may be regulated by RNA structures, RNA processing and RNA-protein complexes. [Display omitted] [ABSTRACT FROM AUTHOR]