Human DAZL, DAZ and BOULE genes modulate primordial germ cell and haploid gamete formation

Center for Human Embryonic Stem Cell Research and Education, Institute for Stem Cell Biology & Regenerative Medicine, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford University, Palo Alto, California 94305, USA.
Nature (Impact Factor: 41.46). 11/2009; 462(7270):222-5. DOI: 10.1038/nature08562
Source: PubMed


The leading cause of infertility in men and women is quantitative and qualitative defects in human germ-cell (oocyte and sperm) development. Yet, it has not been possible to examine the unique developmental genetics of human germ-cell formation and differentiation owing to inaccessibility of germ cells during fetal development. Although several studies have shown that germ cells can be differentiated from mouse and human embryonic stem cells, human germ cells differentiated in these studies generally did not develop beyond the earliest stages. Here we used a germ-cell reporter to quantify and isolate primordial germ cells derived from both male and female human embryonic stem cells. By silencing and overexpressing genes that encode germ-cell-specific cytoplasmic RNA-binding proteins (not transcription factors), we modulated human germ-cell formation and developmental progression. We observed that human DAZL (deleted in azoospermia-like) functions in primordial germ-cell formation, whereas closely related genes DAZ and BOULE (also called BOLL) promote later stages of meiosis and development of haploid gametes. These results are significant to the generation of gametes for future basic science and potential clinical applications.

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Available from: Renee A Reijo Pera, Dec 05, 2014
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    • "negative results. Human pluripotent stem cells (hPSCs), including human embryonic stem cells (hESCs), represent a unique system by which investigators can examine the effects of toxicants as these cells can be differentiated into any cell type in the adult organism, including germ cells[4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]. Recently, we demonstrated that male human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) are directly differentiated into adult-type spermatogonial stem cells/spermatogonia, pre-meiotic and post-meiotic spermatocytes, and post-meiotic spermatids[5]. "
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    ABSTRACT: Environmental influences and insults by reproductive toxicant exposure can lead to impaired spermatogenesis or infertility. Understanding how toxicants disrupt spermatogenesis is critical for determining how environmental factors contribute to impaired fertility. While current animal models are available, understanding of the reproductive toxic effects on human fertility requires a more robust model system. We recently demonstrated that human pluripotent stem cells can differentiate into spermatogonial stem cells/spermatogonia, primary and secondary spermatocytes, and haploid spermatids; a model that mimics many aspects of human spermatogenesis. Here, using this model system, we examine the effects of 2-bromopropane (2-BP) and 1,2,dibromo-3-chloropropane (DBCP) on in vitro human spermatogenesis. 2-BP and DBCP are non-endocrine disrupting toxicants that are known to impact male fertility. We show that acute treatment with either 2-BP or DBCP induces a reduction in germ cell viability through apoptosis. 2-BP and DBCP affect viability of different cell populations as 2-BP primarily reduces spermatocyte viability, whereas DBCP exerts a much greater effect on spermatogonia. Acute treatment with 2-BP or DBCP also reduces the percentage of haploid spermatids. Both 2-BP and DBCP induce reactive oxygen species (ROS) formation leading to an oxidized cellular environment. Taken together, these results suggest that acute exposure with 2-BP or DBCP causes human germ cell death in vitro by inducing ROS formation. This system represents a unique platform for assessing human reproductive toxicity potential of various environmental toxicants in a rapid, efficient, and unbiased format. Copyright © 2015. Published by Elsevier B.V.
    Stem Cell Research 03/2015; 101(3). DOI:10.1016/j.scr.2015.03.002 · 3.69 Impact Factor
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    • "DAZL is sonamed on account of close homology with the earlier-discovered DAZ, which lies on the Y chromosome and has been implicated as the critical gene within the AZF (azoospermia factor) region, so-named as deletions of this region causing non-obstructive spermatogenetic failure (azoospermia)(Reijo et al., 1996). Modulation of human germ cell formation and developmental progression , using primordial germ cells derived from human embryonic stem cells, show that DAZL has a key role in primordial germ cell formation, whereas closely related genes DAZ and BOULE (an additional member of the DAZ gene family) promote later stages of meiosis and development of haploid gametes (Kee et al., 2009). DAZL (À/À) mice are infertile and lack any formation of spermatozoa because of the failure of germ cell differentiation beyond the A spermatogonia level (Schrans-Stassen et al., 2001). "
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    ABSTRACT: Testicular germ cell tumour (TGCT) is the most common cause of cancer in young men (aged 15–45 years) in many populations. Multiple genome-wide association studies (GWAS) of TGCT have now been conducted, yielding over 25 disease-associated single-nucleotide polymorphism (SNP)s at 19 independent loci. The genes at these loci have provided rich biological and genetic insight into possible mechanisms underlying testicular germ cell oncogenesis. In this review, we summarize these mechanisms which can be grouped into five distinct categories: KIT/KITLG signalling, other pathways of male germ cell development/differentiation, telomerase function, microtubule assembly and DNA damage repair. The TGCT risk markers identified through GWAS include individual SNPs carrying per allele odds ratios (OR) in excess of 2.5. These ORs are among the highest reported in GWAS of any cancer type, hence suggesting a potential clinical utility in risk determination. Here, we present analysis of such an approach, using polygenic risk scores to calculate the combined effect of all risk loci on overall TGCT risk and discuss how a potential screening strategy may fit within a broader clinical context.
    Andrology 01/2015; 3(1). DOI:10.1111/andr.304 · 2.30 Impact Factor
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    • "These results suggest that RA and SCF induce the differentiation of human SSCs from cryptorchid patients and OA patients into meiotic male germ cells and haploid cells at transcriptional levels. To determine whether RA and SCF could initiate the meiosis stage of male germ cells, meiotic progression was performed by examining the expression of SCP3, CREST, and MLH1, specific markers for meiosis (Kee et al., 2009; Panula et al., 2011). Meiotic spreads of human SSCs without or with SCF and RA treatment from cryptorchid patients and OA patients were analyzed by immunostaining with antibodies against SCP3 for detecting axial/ lateral elements of the synaptonemal complex, MLH1 for measuring the meiotic recombination frequency, and CREST for determining centromeric regions (Holloway et al., 2008). "
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    ABSTRACT: Generation of functional spermatids from azoospermia patients is of unusual significance in the treatment of male infertility. Here, we report an efficient approach to obtain human functional spermatids from cryptorchid patients. Spermatogonia remained whereas meiotic germ cells were rare in cryptorchid patients. Expression of numerous markers for meiotic and postmeiotic male germ cells was enhanced in human spermatogonial stem cells (SSCs) of cryptorchidism patients by retinoic acid (RA) and stem cell factor (SCF) treatment. Meiotic spreads and DNA content assays revealed that RA and SCF induced a remarkable increase of SCP3-, MLH1-, and CREST-positive cells and haploid cells. Single-cell RNA sequencing analysis reflected distinct global gene profiles in embryos derived from round spermatids and nuclei of somatic cells. Significantly, haploid spermatids generated from human SSCs of cryptorchid patients possessed fertilization and development capacity. This study thus provides an invaluable source of autologous male gametes for treating male infertility in azoospermia patients.
    Stem Cell Reports 10/2014; 3(4). DOI:10.1016/j.stemcr.2014.08.004 · 5.37 Impact Factor
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