Identification and characterization of DAZ family genes in Chinese soft-shell turtle (Pelodiscus sinensis).

The DAZ family genes, including boule, dazl, and daz, play pivotal roles in germ cell development and differentiation during gametogenesis in organisms, which have been widely studied in mammals, reptiles, or fishes. Dazl was bisexual expressed in both mitotic and meiotic germ cells, daz was male premeiotic expressed, whereas boule exhibits largely in unisexual meiotic germ cells but bisexual expression in several fishes, however, there is lack of report on boule gene and the evolutionary conservation and divergence of dazl and boule in reptile. Here, both boule and dazl genes were characterized in Pelodiscus sinensis. The quantitative real-time polymerase chain reaction analysis showed that boule and dazl were abundantly expressed in adult ovary and testis but barely in somatic tissues, such as heart, brain, liver, spleen, and kidney. Moreover, through fluorescent in situ hybridization, bisexual and germline-specific expression profiles of boule and dazl messenger RNAs (mRNAs) were demonstrated. Boule mRNA exhibited a maximal meiotic expression in spermatocytes, and a relatively low, but distinct expression in oocytes at meiotic stages in P. sinensis, similar to the expression profile of human boule in ovary. However, dazl mRNA was richly distributed in male germ cells at almost all stages during spermatogenesis, and predominantly expressed in most of stages of oocytes including premeiotic and meiotic stages. These findings imply that boule and dazl would play distinct roles in the sexual differentiation of germ cells during turtle gametogenesis, and the major functions of daz family members involved in germ cell differentiation would be conserved across species including P. sinensis.

Age-related and photoperiodic variation of the DAZ gene family in the testis of the Syrian hamster (Mesocricetus auratus).

SummaryThe Deleted in AZoospermia (DAZ) gene family regulates the development, maturation and maintenance of germ cells and spermatogenesis in mammals. The DAZ family consists of two autosomal genes, Boule and Dazl (Daz-like), and the Daz gene on chromosome Y. The aim of this study was to analyze the localization of DAZL and BOULE during testicular ontogeny of the seasonal-breeding Syrian hamster, Mesocricetus auratus. We also evaluated the testicular expression of DAZ family genes under short- or long-photoperiod conditions. In the pre-pubertal and adult testis, DAZL protein was found mainly in spermatogonia. BOULE was found in the spermatogonia from 20 days of age and during the pre-pubertal and adult period it was also detected in spermatocytes and round spermatids. DAZL and BOULE expression in spermatogonia was strictly nuclear only in 20-day-old hamsters. We also detected the novel mRNA and protein expression of BOULE in Leydig cells. In adult hamsters, Dazl expression was increased in regressed testis compared with non-regressed testis and DAZL protein expression was restricted to primary spermatocytes in regressed testis. These results show that DAZL and BOULE are expressed in spermatogonia at early stages in the Syrian hamster, then both proteins translocate to the cytoplasm when meiosis starts. In the adult regressed testis, the absence of DAZL in spermatogonia might be related to the decrease in germ cell number, suggesting that DAZ gene family expression is involved in changes in seminiferous epithelium during photoregression.

[Long-term effects of neonatal exposure to bisphenol A on testes structure and the expression of Boule in testes of male mice].

OBJECTIVE: To investigate the long-term effects and the mechanism of neonatal bisphenol A( BPA) exposure on mouse testicular structure and Boule expression. METHODS: A total of 12 pregnant ICR mice were randomly divided into three groups:blank control group, negative control group( corn oil) and BPA 100 µg/kg group. After delivery, BPA was given daily by neck subcutaneous injection to the offspring male mice from postnatal day( PND 1) to PND 21. The offspring male mice were sacrificed on PND35 and PND 70. Morphological changes of testes were detected with hematoxylin-eosin staining, the level of Boule mRNA expression was determined by RT-PCR, the expression of Boule protein was detected by immunofluorescence and Western blotting. RESULTS: Compared with blank control group and negative control group, the diameter and the epithelium thickness of seminiferous epithelium in the same period( PND 35, PND 70)were significantly decreased and the lumen was significantly increased( P < 0. 05) in the testes of BPA( 100 µg/kg) group. In addition, the expressions of Boule mRNA and protein were decreased remarkably( P < 0. 05, P < 0. 01) in testes of BPA 100 µg/kg group. CONCLUSION: Neonatal BPA exposure has a long-term effect on mouse testicular development and may affect testicular development by decreasing the expression of Boule mRNA and protein in testes.

The boule gene is essential for spermatogenesis of haploid insect male.

boule (bol), a member of the Deleted in Azoospermia (DAZ) gene family plays an important role in meiosis (reductional maturation divisions) in a spermatogenesis-specific manner in animals by regulating translation of the downstream cell division cycle 25 (cdc25) phosphatase mRNA. Orthologues of bol are conserved among animals and found in the genomes of hymenopteran insects, in which the general mode of reproduction is haplodiploidy: female is diploid and male is haploid. In this mode of reproduction, haploid males produce haploid sperm through non-reductional maturation divisions. The question thus arises of whether the bol gene actually functions during spermatogenesis in these haploid males. In this study, we identified two transcriptional isoforms of bol orthologue (Ar bol and Ar bol-2), and one cdc25 orthologue (Ar cdc25) in the hymenopteran sawfly, Athalia rosae. Ar bol was expressed exclusively in the testis when maturation divisions occurred, while Ar bol-2 was expressed ubiquitously. Knockdown of all bol transcripts (both Ar bol and Ar bol-2) resulted in a lack of mature sperm, whereas males with sole knockdown of Ar bol-2 were able to produce a small number of mature sperm. The cell cycle was arrested before maturation divisions in the testis in which all bol transcripts were knocked down, as revealed by flow cytometry. Although no mature sperm was produced, sperm elongation was partially observed when Ar cdc25 alone was knocked down. These results indicate that Ar bol is essential for the entry and progression of maturation divisions and sperm differentiation in haploid males.

Boule gene expression underpins the meiotic arrest in spermatogenesis in male rainbow trout (Oncorhynchus mykiss) exposed to DEHP and butachlor.

Boule, the ancestor of the DAZ (Deleted in AZoospermia) gene family, in most organisms is mainly involved in male meiosis. The present study investigates the effects of the plasticizer DEHP (50mg/kg body weight) and herbicide butachlor (0.39mg/L) on male rainbow trout (Oncorhynchus mykiss) for a 10-day period in two independent experiments. The results showed that plasma testosterone (T) concentrations were significantly lower in fish exposed to either DEHP or butachlor compared to the control fish (P<0.05). Fish showed a significantly elevated hepatosomatic index (HSI) in the butachlor treatment (P<0.05). However, no significant difference was observed in HSI values in the DEHP treatment (P>0.05). In addition, no significant differences were found in the gonadosomatic index (GSI) in both DEHP and butachlor treatments (P>0.05). Histologically, testes of male trout in the control groups were well differentiated and filled with large numbers of cystic structures containing spermatozoa. In contrast, the testes of male trout contained mostly spermatocytes with few spermatozoa in both treated group, suggesting that DEHP and butachlor may inhibit the progression of meiosis. Also, boule gene expression was significantly lower in the testes of male trout affected by DEHP and butachlor in comparison with their control groups (P<0.05), which confirmed the meiotic arrest in affected trout. Based on the results, the present study demonstrated that DEHP and butachlor can inhibit the progression of spermatogenesis in male trout, potentially by causing an arrest of meiosis, maybe due to down-regulation of boule gene expression through T and/or IGF1 via ERK1/2 signaling in T-independent pathways. In addition, these results confirmed that boule can be considered as a predictive marker to assess meiotic efficiency.

Scent of a mite: origin and chemical characterization of the lemon-like flavor of mite-ripened cheeses.

Cheese infested with cheese mites is usually treated as unpalatable. Nevertheless, some traditional cheese manufactories in Germany and France intentionally use mites for fermentation of special varieties (i.e. Milbenkäse and Mimolette). While their production includes different mite species, both are characterized by a "lemon-like" flavor. However, the chemical nature and origin of this flavor-component is unknown. The cheese mites possess a pair of opisthosomal glands producing blends of hydrocarbons, terpenes and aromatics. Here, we describe the chemical profiles of the astigmatid mite species Tyrolichus casei (Milbenkäse) and Acarus siro (Mimolette). Although the chemical profiles differ in several aspects, both mite species produce neral (a volatile flavor component of lemon oil), which was absent from the headspace of both cheeses without mites. We conclude that the lemon-like flavor of mite cheese is not a consequence of fermentation of the cheese itself but a component from secretions of the cheese mites.

[5'-flanking regulatory sequence methylation of the Boule gene in the testis tissue of infertile men with Sertoli cell-only syndrome].

OBJECTIVE: To investigate the 5'-flanking regulatory sequence methylation status of the Boule gene in the testis tissue of infertile men with Sertoli cell-only syndrome (SCOS). METHODS: We collected biopsy samples of the testis tissue from 12 men with obstructive azoospermia (the control group) and 15 cases of SCOS, all without varicocele, cryptorchidism, or infectious disease. We extracted genomic DNA from the testis tissue of the SCOS patients, analyzed the characteristics of the 5'-flanking regulatory sequence of the Boule gene using the bioinformatics method, and detected the methylation status of the Boule gene by sodium bisulfite sequencing. RESULTS: A CpG island was observed in the 5'-flanking regulation region of the Boule gene. The methylation level of the Boule gene was remarkably higher in the SCOS group than in the obstructive azoospermia controls (61.4% vs 21.7%, P<0.01), with significant differences in the methylation levels of 14 CpG sites, namely, －58 bp, －50 bp, －48 bp, －38 bp, －28 bp, －24 bp, －20 bp, －15 bp, －1 bp, +5 bp, +8 bp, +15 bp, +29 bp, and +58 bp. CONCLUSIONS: The methylation level of the Boule gene is significantly higher in the SCOS patients than in the obstructive azoospermia males, which suggests that the changes in Boule methylation may be associated with spermatogenic dysfunction.

Novel Genome-Wide Interactions Mediated via BOLL and EDNRA Polymorphisms in Intracranial Aneurysm.

OBJECTIVE: The association between boule (BOLL) and endothelin receptor type A (EDNRA) loci and intracranial aneurysm (IA) formation has been reported via genome-wide association studies. We sought to identify genome-wide interactions involving BOLL and EDNRA loci for IA in a Korean adult cohort. METHODS: Genome-wide pairwise interaction analyses of BOLL and EDNRA involving 250 patients with IA and 296 controls were performed using the additive effect model after adjusting for confounding factors. RESULTS: Among 512575 single-nucleotide polymorphisms (SNPs), 23 and 11 common SNPs suggested a genome-wide interaction threshold (p<1.25×10-8) involving rs700651 (BOLL) and rs6841581 (EDNRA). Rather than singe SNP effect of BOLL or EDNRA on IA development, they showed a synergistic effect on IA formation via multifactorial pair-wise interactions. The rs1105980 of PTCH1 gene showed the most significant interaction with rs700651 (natural log-transformed odds ratio [lnOR], 1.53; p=6.41×10-11). The rs74585958 of RYK gene interacted strongly with rs6841581 (lnOR, -19.91; p=1.64×10-9). Although, there was no direct interaction between BOLL and EDNRA variants, two EDNRA-interacting gene variants of TNIK (rs11925024 and rs1231) and FTO (rs9302654), and one BOLL-interacting METTL4 gene variant (rs549315) exhibited marginal interaction with BOLL gene. CONCLUSION: BOLL or EDNRA may have a synergistic effect on IA formation via multifactorial pair-wise interactions.

RNA binding protein BOULE forms aggregates in mammalian testis.

Amyloids have traditionally been considered pathologic protein aggregates which contribute to neurodegeneration. New evidence however increasingly suggests that non-pathological amyloids are formed in animals during normal development. Amyloid-like aggregate formation was originally thought to be a conserved feature of animal gametogenesis. This hypothesis was based on findings which suggest that regulated amyloid formations govern yeast meiosis by way of meiosis-specific RNA binding proteins. Additional support came from studies which demonstrate that DAZL, a mammalian gametogenesis-specific RNA binding protein, also forms SDS-resistant aggregates in vivo. Here, we report evidence of aggregated BOULE formations, another DAZ family protein, during sperm development. Data suggest that in mouse testis, BOULE forms SDS-resistant amyloid-like aggregates. BOULE aggregate formation correlates with dynamic developmental expression during spermatogenesis but disappeared in Boule knockout testis. We also mapped essential small region in vitro BOULE aggregations, immediately downstream DAZ repeats, and found that aggregations positively correlated with temperature. We also performed enhanced UV cross-linking immunoprecipitation on BOULE aggregates from mouse testes and found that aggregates bind with a large number of spermatogenesis-related mRNAs. These findings provide insight into the amyloidogenic properties of gametogenesis-specific RNA binding proteins as a conserved feature in mammalian reproduction. Further investigation is warranted to understand the functional significance of BOULE amyloid-like formation during mouse spermatogenesis.

The Buccal Fat Pad Flap.

This article presents an overview of the history of the buccal fat pad flap, its relevant anatomy, and its indications and contraindications. The surgical technique for its harvest is described, as are the postoperative care and possible complications.

Direct reprogramming of human Sertoli cells into male germline stem cells with the self-renewal and differentiation potentials via overexpressing DAZL/DAZ2/BOULE genes.

We propose a new concept that human somatic cells can be converted to become male germline stem cells by the defined factors. Here, we demonstrated that the overexpression of DAZL, DAZ2, and BOULE could directly reprogram human Sertoli cells into cells with the characteristics of human spermatogonial stem cells (SSCs), as shown by their similar transcriptomes and proteomics with human SSCs. Significantly, human SSCs derived from human Sertoli cells colonized and proliferated in vivo, and they could differentiate into spermatocytes and haploid spermatids in vitro. Human Sertoli cell-derived SSCs excluded Y chromosome microdeletions and assumed normal chromosomes. Collectively, human somatic cells could be converted directly to human SSCs with the self-renewal and differentiation potentials and high safety. This study is of unusual significance, because it provides an effective approach for reprogramming human somatic cells into male germ cells and offers invaluable male gametes for treating male infertility.

Antimicrobial Activity and Composition of Five Rosmarinus (Now Salvia spp. and Varieties) Essential Oils.

Salvia rosmarinus Spenn. and Salvia jordanii J.B.Walker are aromatic evergreen shrubs belonging to the Lamiaceae family. Their aerial parts have been used since ancient times as natural preservatives. The present study reported the investigation of the chemical profile and the extraction yield of the essential oils (EOs) obtained from the dried aerial parts of four cultivars of Salvia rosmarinus ('Boule'; 'Vicomte de Noailles'; 'Gorizia'; 'Joyce de Baggio') and the species S. jordanii, together with their antibacterial and antifungal activities. The phytochemical investigation evidenced a predominance of oxygenated monoterpenes in all the samples (57.5-77.1%), except in 'Boule', in which the hydrocarbon form prevailed (50.2%). Principal Component Analysis (PCA) of the matrix taxa × compounds showed that nine compounds have a significant discriminating function between the samples. 'Vicomte de Noailles' was characterized by high amounts of camphor and 14-hydroxy-9-epi-(E)-caryophyllene, while 'Gorizia' and Jord differed in their predominance of camphene, borneol, bornyl acetate, and α-humulene. Lastly, 'Boule' and 'Joyce de Baggio' segregated separately and were characterized by high amounts of α-pinene, myrcene, and verbenone. The selected EOs presented a moderate antibacterial activity on the tested bacterial strains and resulted not active on the tested yeast species.

Induction of goat bone marrow mesenchymal stem cells into putative male germ cells using mRNA for STRA8, BOULE and DAZL.

Bone mesenchymal stem cells (BMSCs) have the capacity to differentiate into germ cells (GCs). This study was conducted to develop a non-integrated method of using RNA transfection to derive putative male GCs from goat BMSCs (gBMSCs) in vitro by overexpressing STRA8, BOULE and DAZL. The gBMSCs were induced by co-transfection these three mRNAs together (mi-SBD group) or sequential transfection according to their expression time order in vivo (mi-S + BD group). After transfection, a small population of gBMSCs transdifferentiated into early germ cell-like cells and had the potential to enter meiosis. These cells expressed primordial germ cell specific genes STELLA, C-KIT and MVH, as well as premeiotic genes DAZL, BOULE, STRA8, PIWIL2 and RNF17. Importantly, the expression level of meiotic marker synaptonemal complex protein 3 significantly increased in these transfected two groups compared with control cells by qRT-PCR, immunofluorescence and western blot analysis (P < 0.05). Moreover, the protein expression of MVH was significantly higher in mi-S + BD group than that in mi-SBD group (P < 0.05). In addition, compared with control group, the methylation rate of imprinted gene H19 decreased in these two transfected group (P < 0.05), and the rate was significantly lower in mi-S + BD group compared with mi-SBD group (P < 0.05). This study helps to understand the mechanisms of action of key genes in GCs differentiation and also provides a novel system for in vitro induction of male GCs from stem cells.

Polymorphisms within the Boule Gene Detected by Tetra-Primer Amplification Refractory Mutation System PCR (T-ARMS-PCR) are Significantly Associated with Goat Litter Size.

As a gene contributing to spermatogenesis, the Boule gene (also called Boll), whose mutations result in azoospermia and sterility of flies and mice, was conserved in reductional maturation divisions. However, in goats, the polymorphisms of Boule, especially with regard to their fundamental roles in female reproduction traits, are still unknown. Therefore, the aims of this study were to detect a potential mutation (rs661484476: g.7254T>C) located in intron 2 of the Boule gene by tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR) and to explore its potential association with the litter size of Shaanbei White-Cashmere goats (SBWGs). In this study, g.7254T>C was firstly detected. The TT genotype was the dominant genotype in the single-lamb group, and T was also the dominant allele in all tested groups. Additionally, the detected locus displayed moderate polymorphism with polymorphism information content (PIC) values among all studied goats ranging from 0.303 to 0.344. Notably, according to the χ2 test, the distribution differences for the genotypic frequencies between the single- and multi-lamb groups was significant (p = 0.014). Furthermore, the polymorphisms of the goat Boule gene were significantly associated with the goat litter size in SBWGs (p < 0.05), which indicated that g.7254T>C could be a potential marker in the marker-assisted selection process for potential litter size in goats. These results also indicated that the Boule gene might exercise important functions in female goat reproduction, which provided new insight for female goat breeding and could accelerate the process of goat breeding.

Goat Boule: Isoforms identification, mRNA expression in testis and functional study and promoter methylation profiles.

A conserved gene in meiosis, the Boule gene is involved in meiosis and spermatogenesis. The deletion of this gene in males blocks meiosis and results in infertility. Alternative splicing variants of the Boule gene have been identified in humans, bovines, and bats, but in dairy goats remains unknown. This study was therefore to detect splicing variants of the goat Boule gene and explore their potential roles in meiosis. Three isoforms, denoted as Boule-a, Boule-b, and Boule-c, were identified in the testes of goats using real-time PCR (RT-PCR) and cloning sequencing. Compared to the normal Boule gene, Boule-a was found to lack exons 7 and 8, which corresponds to a predicted variant, X4, on the NCBI database. Boule-b lacked exon 8, and Boule-c only retained exons 1 and 2. Of these three variants, two were novel isoforms of the Boule gene. Quantitative RT-PCR (qRT-PCR) showed that the Boule-a and Boule-b expression patterns were significantly different between the adult goat testes and the postnatal testes of 42 and 56 days. Overexpression of Boule-a and Boule-c in GC-1 spg cells of model mice significantly repressed CDC2 expression. Bisulfite sequencing PCR (BSP) results showed that the promoter region of the Boule gene was hypermethylated in goat testes. A negative correlation between the methylation levels of the Boule gene promoter and total mRNA expression of its transcripts was found. Our data showed alternative splicing and promoter methylation in the goat Boule gene, suggesting that this gene may play an important role in the regulation of Boule expression and in meiosis processing.

Overexpression of STRA8, BOULE, and DAZL Genes Promotes Goat Bone Marrow-Derived Mesenchymal Stem Cells In Vitro Transdifferentiation Toward Putative Male Germ Cells.

Bone marrow mesenchymal stem cells (BMSCs), which are well characterized and widely utilized adult stem cells, encompass the capacity to commit to a variety of cell types. This study was conducted to develop an effective way to induce goat BMSCs (gBMSCs) to transdifferentiate toward putative male germ cells by overexpressing STRA8 (stimulated by RA-8), BOULE (also called BOLL), and DAZL (deleted in azoospermia-like). First, we found that the expression levels of these 3 genes gradually increased during development of the goat testis from 10 days postnatal to 8 months old. Therefore, we hypothesized that overexpressing these genes might contribute to the transdifferentiation of gBMSCs toward germ cells. We then overexpressed, separately and in combination, STRA8, BOULE, and DAZL in gBMSCs. Our results showed that a small population of transfected gBMSCs transdifferentiated into early goat germ cell-like cells and that these cells expressed primordial germ cell specification genes STELLA (also known as DPPA3, developmental pluripotency associated 3) and C-KIT (tyrosine kinase receptor) as well as premeiotic genes MVH (mouse vasa homolog), DAZL, BOULE, STRA8, PIWIL2 (piwi-like RNA-mediated gene silencing 2), and RNF17 (ring finger protein 17). Importantly, results from quantitative reverse transcription polymerase chain reaction, immunofluorescence, and Western blot analysis showed that the meiotic marker synaptonemal complex protein 3 (SCP3) significantly increased in transfected cells compared to untransfected control cells ( P < .05). Additionally, the co-overexpression group cells had the highest SCP3 messenger RNA and protein expression levels, which indicated that 3-gene co-overexpression had the highest potential to transdifferentiate gBMSCs to germ cells. Taken together, these results demonstrate that the overexpression of STRA8, BOULE, and DAZL was able to promote the transdifferentiation of gBMSCs to early goat germ cell-like cells in vitro, which probably enhanced maturation and progression through meiosis. This approach would be important to generating gametes for future basic science as well as for potential clinical applications.

"How nationality influences Opinion": Darwinism and palaeontology in France (1859-1914).

This paper discusses the "non-reception" of Darwin's works and concepts in French palaeontology and palaeoanthropology between 1859 and 1914. Indeed, this integration was difficult, biased and belated, for ideological, intellectual and epistemological reasons: Clémence Royer's biased 1862 translation of Darwin's Origin of Species pulled its ideas toward "social darwinism", making them less attractive to the natural sciences. - French nationalism and the authority of religion, which imposed Cuvier's thinking until late into the century - the dominance of Lamarckian and neo-Lamarckian transformism in France, both in biology and in paleontology, which proposed the notion of orthogenetic laws and environmental determinations, and refused darwinian evolutionary mechanisms - obstacles inherent to the application of Darwin's concepts to palaeontology, namely the impossibility to identify evolutionary mechanisms through the fossil record, which was stressed by Darwin himself and underlined in turn by 19th century French palaeontologists. However, as I argue, in the course of the examined period, French palaeontology grew from refusal to a better understanding and evaluation of Darwin's thinking. The quest for intermediary forms, the construction of branching evolutionary trees and the attempts to reconstruct human biological and cultural evolution were important efforts toward an integration of some aspects of Darwinian views and practices into French palaeontology and plaeoanthropology. The 1947 Paris conference which brought together American Neo-darwinists and French paleontologists made Darwinian concepts better understood and triggered a revival of French palaeontology from the 1960s.

Neonatal bisphenol A exposure induces meiotic arrest and apoptosis of spermatogenic cells.

Bisphenol A (BPA) is a widely used industrial plasticizer, which is ubiquitously present in the environment and organisms. As an endocrine disruptor, BPA has caused significant concerns regarding its interference with reproductive function. However, little is known about the impact of BPA exposure on early testicular development. The aim of the present study was to investigate the influence of neonatal BPA exposure on the first wave of spermatogenesis. Newborn male mice were subcutaneously injected with BPA (0.01, 0.1 and 5 mg/kg body weight) daily from postnatal day (PND) 1 to 21. Histological analysis of testes at PND 22 revealed that BPA-treated testes contained mostly spermatogonia and spermatocytes with markedly less round spermatids, indicating signs of meiotic arrest. Terminal dUTP nick-end labeling (TUNEL) assay showed that BPA treatment significantly increased the number of apoptotic germ cells per tubule, which corroborated the observation of meiotic arrest. In addition, BPA caused abnormal proliferation of germ cells as revealed by Proliferating Cell Nuclear Antigen (PCNA) immunohistochemical staining. Mechanistically, BPA-treated testes displayed a complete lack of BOULE expression, which is a conserved key regulator for spermatogenesis. Moreover, BPA significantly increased the expression of estrogen receptor (ER) α and ß in the developing testis. The present study demonstrated that neonatal BPA exposure disrupted meiosis progression during the first wave of spermatogenesis, which may be, at least in part, due to inhibition of BOULE expression and/or up-regulation of ERα/ß expression in BPA-exposed developing testis.

DAZ Family Proteins, Key Players for Germ Cell Development.

DAZ family proteins are found almost exclusively in germ cells in distant animal species. Deletion or mutations of their encoding genes usually severely impair either oogenesis or spermatogenesis or both. The family includes Boule (or Boll), Dazl (or Dazla) and DAZ genes. Boule and Dazl are situated on autosomes while DAZ, exclusive of higher primates, is located on the Y chromosome. Deletion of DAZ gene is the most common causes of infertility in humans. These genes, encoding for RNA binding proteins, contain a highly conserved RNA recognition motif and at least one DAZ repeat encoding for a 24 amino acids sequence able to bind other mRNA binding proteins. Basically, Daz family proteins function as adaptors for target mRNA transport and activators of their translation. In some invertebrate species, BOULE protein play a pivotal role in germline specification and a conserved regulatory role in meiosis. Depending on the species, DAZL is expressed in primordial germ cells (PGCs) and/or pre-meiotic and meiotic germ cells of both sexes. Daz is found in fetal gonocytes, spermatogonia and spermatocytes of adult testes. Here we discuss DAZ family genes in a phylogenic perspective, focusing on the common and distinct features of these genes, and their pivotal roles during gametogenesis evolved during evolution.

IGF1 regulation of BOULE and CDC25A transcripts via a testosterone-independent pathway in spermatogenesis of adult mice.

The Deleted in AZoospermia (DAZ) gene family plays an essential role in spermatogenesis and fertility in mammals. This gene family contains two autosomal genes, BOULE and DAZL (DAZ-Like), and the DAZ gene cluster in the Y chromosome. CDC25A (a cell cycle regulator) has been proposed as a putative substrate for the RNA-binding proteins of DAZ family. However, mechanisms regulating DAZ gene expression have been poorly investigated. We analyzed immunohistochemical localization of DAZL, BOULE and CDC25A, as well as the involvement of testosterone (T) and insulin-like growth factor 1 (IGF1) in the modulation of mRNA expression for DAZL, BOULE and CDC25A in the adult mouse testes. It was found that DAZL was mostly immunolocalized in spermatogonia, while BOULE and CDC25A were detected in spermatocytes and round spermatids. Three-color immunofluorescence showed that DAZL-positive cells also expressed proliferating cell nuclear antigen (PCNA). In vitro incubation of the testes showed that neither T nor IGF1 affected DAZL mRNA expression. However, either T or IGF1 increased BOULE mRNA expression. Antiandrogen flutamide abolished the T-induced increase in BOULE mRNA, but had no effect on the IGF1 induced increase in the mouse testes. Extracellular-signal-regulated kinase 1/2 (ERK1/2) inhibitor, U0126, prevented IGF1-induction of BOULE mRNA. It was found that IGF1 increased CDC25A mRNA expression and that U0126 - but not flutamide - abolished the IGF1-induced CDC25A mRNA expression. These results showed that IGF1 regulated the expression of BOULE and CDC25A mRNAs via ERK1/2 signaling and in T-independent pathway during spermatogenesis in the adult mouse testes.