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Gadek M, Sherr EH, Floor SN. The variant landscape and function of DDX3X in cancer and neurodevelopmental disorders. Trends Mol Med 2023; 29:726-739. [PMID: 37422363 DOI: 10.1016/j.molmed.2023.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 07/10/2023]
Abstract
RNA molecules rely on proteins across their life cycle. DDX3X encodes an X-linked DEAD-box RNA helicase with a Y-linked paralog, DDX3Y. DDX3X is central to the RNA life cycle and is implicated in many conditions, including cancer and the neurodevelopmental disorder DDX3X syndrome. DDX3X-linked conditions often exhibit sex differences, possibly due to differences between expression or function of the X- and Y-linked paralogs DDX3X and DDX3Y. DDX3X-related diseases have different mutational landscapes, indicating different roles of DDX3X. Understanding the role of DDX3X in normal and disease states will inform the understanding of DDX3X in disease. We review the function of DDX3X and DDX3Y, discuss how mutation type and sex bias contribute to human diseases involving DDX3X, and review possible DDX3X-targeting treatments.
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Affiliation(s)
- Margaret Gadek
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
| | - Elliott H Sherr
- Department of Neurology, University of California, San Francisco, CA 94143, USA
| | - Stephen N Floor
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA 94143, USA.
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2
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Matsumura T, Endo T, Isotani A, Ogawa M, Ikawa M. An azoospermic factor gene, Ddx3y and its paralog, Ddx3x are dispensable in germ cells for male fertility. J Reprod Dev 2019; 65:121-128. [PMID: 30613052 PMCID: PMC6473106 DOI: 10.1262/jrd.2018-145] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
About 10% of male infertile patients show abnormalities in spermatogenesis. The microdeletion of azoospermia factor a (AZFa) region of the Y chromosome is thought to be a
cause of spermatogenic failure. However, candidate gene responsible for the spermatogenic failure in AZFa deleted patients has not been elucidated yet. Using mice, we
explored the function of Ddx3y, a strong candidate gene in the Azfa region, and Ddx3x, a Ddx3y paralog on the X
chromosome, in spermatogenesis. We first generated Ddx3y KO male mice using CRISPR/Cas9 and found that the Ddx3y KO male mice show normal spermatogenesis,
produce morphologically normal spermatozoa, and sire healthy offspring. Because Ddx3x KO males were embryonic lethal, we next generated chimeric mice, which contain
Ddx3x and Ddx3y double KO (dKO) germ cells, and found that the dKO germ cells can differentiate into spermatozoa and transmit their mutant alleles to
offspring by normal mating. We conclude that Ddx3x and Ddx3y are dispensable for spermatogenesis at least in mice. Unlike human, mice have an additional
Ddx3y paralog D1pas1, that has been reported to be essential for spermatogenesis. These findings suggest that human and mouse DDX3 related proteins have
distinct differences in their functions.
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Affiliation(s)
- Takafumi Matsumura
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan
| | - Tsutomu Endo
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.,Immunology Frontier Research Center, Osaka University, Osaka 565-0871, Japan
| | - Ayako Isotani
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.,Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara 630-0192, Japan
| | - Masaki Ogawa
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.,Immunology Frontier Research Center, Osaka University, Osaka 565-0871, Japan.,The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
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3
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Nailwal M, Chauhan JB. Azoospermia Factor a (AZFa) sub-region of human Y-chromosome: A review. Meta Gene 2017. [DOI: 10.1016/j.mgene.2017.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Kotov AA, Olenkina OM, Godneeva BK, Adashev VE, Olenina LV. Progress in understanding the molecular functions of DDX3Y (DBY) in male germ cell development and maintenance. Biosci Trends 2017; 11:46-53. [PMID: 28190795 DOI: 10.5582/bst.2016.01216] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Human DDX3 paralogs are housed on the X chromosome (DDX3X) as well as in the non- recombining region Yq11 of the Y-chromosome (DDX3Y or DBY). A gene encoding RNA helicase DDX3Y is located in the AZoospermia Factor a (AZFa) region of the Y-chromosome and expressed only in male germ cells. Deletions encompassing the DDX3Y gene lead to azoospermia and cause Sertoli Cell-Only Syndrome (SCOS) in humans. SCOS is characterized by a complete germ cell lack with preservation of somatic Sertoli cells. This review summarizes current advances in the study of DDX3Y functions in maintenance and development of early male germ cells. Data obtained from a mouse xenotransplantation model reveals that DDX3Y expression is enough to drive germ cell differentiation of AZFa-deleted human induced pluripotent stem cells (iPSCs) and for activation of the specific set of germline developmental genes. Results achieved using the testes of Drosophila demonstrate that DDX3Y homolog Belle is required cell-autonomously for mitotic progression and survival of germline stem cells and spermatogonia as the upstream regulator of mitotic cyclin expression.
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Affiliation(s)
- Alexei A Kotov
- Laboratory of Biochemical Genetics of Animals, Institute of Molecular Genetics, Russian Academy of Sciences
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Comparative Evolution of Duplicated Ddx3 Genes in Teleosts: Insights from Japanese Flounder, Paralichthys olivaceus. G3-GENES GENOMES GENETICS 2015; 5:1765-73. [PMID: 26109358 PMCID: PMC4528332 DOI: 10.1534/g3.115.018911] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Following the two rounds of whole-genome duplication that occurred during deuterostome evolution, a third genome duplication event occurred in the stem lineage of ray-finned fishes. This teleost-specific genome duplication is thought to be responsible for the biological diversification of ray-finned fishes. DEAD-box polypeptide 3 (DDX3) belongs to the DEAD-box RNA helicase family. Although their functions in humans have been well studied, limited information is available regarding their function in teleosts. In this study, two teleost Ddx3 genes were first identified in the transcriptome of Japanese flounder (Paralichthys olivaceus). We confirmed that the two genes originated from teleost-specific genome duplication through synteny and phylogenetic analysis. Additionally, comparative analysis of genome structure, molecular evolution rate, and expression pattern of the two genes in Japanese flounder revealed evidence of subfunctionalization of the duplicated Ddx3 genes in teleosts. Thus, the results of this study reveal novel insights into the evolution of the teleost Ddx3 genes and constitute important groundwork for further research on this gene family.
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Rauschendorf MA, Zimmer J, Ohnmacht C, Vogt PH. DDX3X, the X homologue of AZFa gene DDX3Y, expresses a complex pattern of transcript variants only in the male germ line. Mol Hum Reprod 2014; 20:1208-22. [PMID: 25208899 DOI: 10.1093/molehr/gau081] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
DDX3X, the functional X homologue of the major AZFa gene, DDX3Y, belongs to the highly conserved PL10-subfamily of DEAD-box RNA helicase genes which are functionally conserved from yeast to man. They are mainly involved in cell cycle control and translation initiation control of gene transcripts with long 5'UTR extensions containing complex secondary structures. Interestingly, in humans both gene copies were found to be expressed at different phases of human spermatogenesis. Whereas DDX3Y transcripts are translated only in premeiotic male germ cells, the DDX3X protein is expressed only in postmeiotic spermatids. In this study, we found that the major class of DDX3X transcripts in human testis become activated first after meiosis and at a specific core promoter not active in somatic tissues and not present upstream of the DDX3Y homologue. Two alternative 5'UTR transcript lengths are subsequently produced by an additional testis-specific 5'UTR splicing event. Both transcripts are mainly processed for polyadenylation in their proximal 3'UTR. A minor transcript class starting at the same male germ line-specific core promoter produces primary transcripts with an extremely long 3'UTR (∼ 17 kb), which is subsequently spliced at distinct sites resulting in six short 3'UTR splice variants (I-VI). Comparative analyses of the DDX3X transcripts in mouse and primates revealed that this complex pattern of male germ line-specific transcript variants first evolved in primates. Our data thus suggest complex translational control mechanism(s) for the human DDX3X gene locus functioning only in the male germ line and resulting in expression of its protein only in the postmeiotic spermatids.
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Affiliation(s)
- Marc-Alexander Rauschendorf
- Reproduction Genetics Unit, Department of Gynecological Endocrinology & Reproductive Medicine, University of Heidelberg, Heidelberg, Germany Present address: Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Program of Functional Genomics and Cancer, CNRS UDS UMR 7104, INSERM U 964, 67404 Illkirch Cedex, France
| | - Jutta Zimmer
- Reproduction Genetics Unit, Department of Gynecological Endocrinology & Reproductive Medicine, University of Heidelberg, Heidelberg, Germany
| | - Caroline Ohnmacht
- Reproduction Genetics Unit, Department of Gynecological Endocrinology & Reproductive Medicine, University of Heidelberg, Heidelberg, Germany
| | - Peter H Vogt
- Reproduction Genetics Unit, Department of Gynecological Endocrinology & Reproductive Medicine, University of Heidelberg, Heidelberg, Germany
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Li Q, Zhang P, Zhang C, Wang Y, Wan R, Yang Y, Guo X, Huo R, Lin M, Zhou Z, Sha J. DDX3X regulates cell survival and cell cycle during mouse early embryonic development. J Biomed Res 2014; 28:282-91. [PMID: 25050112 PMCID: PMC4102842 DOI: 10.7555/jbr.27.20130047] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/06/2013] [Accepted: 08/04/2013] [Indexed: 12/13/2022] Open
Abstract
DDX3X is a highly conserved DEAD-box RNA helicase that participates in RNA transcription, RNA splicing, and mRNA transport, translation, and nucleo-cytoplasmic transport. It is highly expressed in metaphase II (MII) oocytes and is the predominant DDX3 variant in the ovary and embryo. However, whether it is important in mouse early embryo development remains unknown. In this study, we investigated the function of DDX3X in early embryogenesis by cytoplasmic microinjection with its siRNA in zygotes or single blastomeres of 2-cell embryos. Our results showed that knockdown of Ddx3x in zygote cytoplasm led to dramatically diminished blastocyst formation, reduced cell numbers, and an increase in the number of apoptotic cells in blastocysts. Meanwhile, there was an accumulation of p53 in RNAi blastocysts. In addition, the ratio of cell cycle arrest during 2-cell to 4-cell transition increased following microinjection of Ddx3x siRNA into single blastomeres of 2-cell embryos compared with control. These results suggest that Ddx3x is an essential gene associated with cell survival and cell cycle control in mouse early embryos, and thus plays key roles in normal embryo development.
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Affiliation(s)
- Qian Li
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Pan Zhang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Chao Zhang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Ying Wang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Ru Wan
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Ye Yang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Xuejiang Guo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Ran Huo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Min Lin
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Zuomin Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Jiahao Sha
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
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8
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Gaspar JA, Doss MX, Winkler J, Wagh V, Hescheler J, Kolde R, Vilo J, Schulz H, Sachinidis A. Gene expression signatures defining fundamental biological processes in pluripotent, early, and late differentiated embryonic stem cells. Stem Cells Dev 2012; 21:2471-84. [PMID: 22420508 DOI: 10.1089/scd.2011.0637] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Investigating the molecular mechanisms controlling the in vivo developmental program postembryogenesis is challenging and time consuming. However, the developmental program can be partly recapitulated in vitro by the use of cultured embryonic stem cells (ESCs). Similar to the totipotent cells of the inner cell mass, gene expression and morphological changes in cultured ESCs occur hierarchically during their differentiation, with epiblast cells developing first, followed by germ layers and finally somatic cells. Combination of high throughput -omics technologies with murine ESCs offers an alternative approach for studying developmental processes toward organ-specific cell phenotypes. We have made an attempt to understand differentiation networks controlling embryogenesis in vivo using a time kinetic, by identifying molecules defining fundamental biological processes in the pluripotent state as well as in early and the late differentiation stages of ESCs. Our microarray data of the differentiation of the ESCs clearly demonstrate that the most critical early differentiation processes occur at days 2 and 3 of differentiation. Besides monitoring well-annotated markers pertinent to both self-renewal and potency (capacity to differentiate to different cell lineage), we have identified candidate molecules for relevant signaling pathways. These molecules can be further investigated in gain and loss-of-function studies to elucidate their role for pluripotency and differentiation. As an example, siRNA knockdown of MageB16, a gene highly expressed in the pluripotent state, has proven its influence in inducing differentiation when its function is repressed.
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Affiliation(s)
- John Antonydas Gaspar
- Center of Physiology and Pathophysiology, Institute of Neurophysiology, University of Cologne, Cologne, Germany
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9
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Rauschendorf MA, Zimmer J, Hanstein R, Dickemann C, Vogt PH. Complex transcriptional control of the AZFa gene DDX3Y in human testis. ACTA ACUST UNITED AC 2011; 34:84-96. [PMID: 20374305 PMCID: PMC3039753 DOI: 10.1111/j.1365-2605.2010.01053.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The human DEAD-box Y (DBY) RNA helicase (aka DDX3Y) gene is thought to be the major azoospermia factor a (AZFa) gene in proximal Yq11. Men with its deletion display no somatic pathologies, but suffer from complete absence of germ cells. Accordingly, DDX3Y protein is expressed only in the germline in spermatogonia, although the transcripts were found in many tissues. Here, we show the complex transcriptional control of a testis-specific DDX3Y transcript class with initiation at different sites upstream of the gene’s open reading frame (5′Untranslated Region; UTR) and with polyadenylation in their proximal 3′UTR. The most distal transcriptional start site (TSS; ∼1 kb upstream) was mapped in MSY2, a Y-specific minisatellite. As this testis-specific 5′UTR was subsequently processed by three alternative splicing events, it has been tentatively designated ‘exon-T’(estis). The MSY2 sequence unit was also found upstream of the mouse Ddx3y gene. However, only after its tandem amplification on the Y chromosome of Platyrrhini (new world monkeys) and Catarrhini (old world monkeys) did MSY2 become part of a novel distal promoter for DDX3Y expression in testis tissue and provides a second transcriptional start site (T-TSS-II) in Catarrhini. We therefore suggest that the development of a novel distal DDX3Y promoter in primates, which is activated only in testis tissue, is probably part of the gene’s germline translation control.
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Affiliation(s)
- M-A Rauschendorf
- Unit of Molecular Genetics & Infertility, Department of Gynecological Endocrinology & Reproductive Medicine, University of Heidelberg, Heidelberg, Germany
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10
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Ewen K, Baker M, Wilhelm D, Aitken RJ, Koopman P. Global survey of protein expression during gonadal sex determination in mice. Mol Cell Proteomics 2009; 8:2624-41. [PMID: 19617587 DOI: 10.1074/mcp.m900108-mcp200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The development of an embryo as male or female depends on differentiation of the gonads as either testes or ovaries. A number of genes are known to be important for gonadal differentiation, but our understanding of the regulatory networks underpinning sex determination remains fragmentary. To advance our understanding of sexual development beyond the transcriptome level, we performed the first global survey of the mouse gonad proteome at the time of sex determination by using two-dimensional nanoflow LC-MS/MS. The resulting data set contains a total of 1037 gene products (154 non-redundant and 883 redundant proteins) identified from 620 peptides. Functional classification and biological network construction suggested that the identified proteins primarily serve in RNA post-transcriptional modification and trafficking, protein synthesis and folding, and post-translational modification. The data set contains potential novel regulators of gonad development and sex determination not revealed previously by transcriptomics and proteomics studies and more than 60 proteins with potential links to human disorders of sexual development.
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Affiliation(s)
- Katherine Ewen
- Division of Molecular Genetics and Development, The University of Queensland, Brisbane, Queensland 4072, Australia
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11
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Abstract
Evolving therapies have allowed the use of sperm from men with spermatogenic compromise, obstructive azoospermia, and sperm functional deficiency, enabling these men to procreate when unable to do so naturally. The genetic basis of only a portion of these conditions is known and research must be pursued into the genetic underpinnings of those that have not yet been delineated. Education and provision of information to patients is the responsibility of all involved in the care of men with reproductive failure. The author concentrates on some of the known causes of nonobstructive azoospermia and obstructive azoospermia with a well-established genetic cause such as congenital bilateral absence of the vas deferens.
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Affiliation(s)
- Robert D Oates
- Department of Urology, Boston University School of Medicine, 720 Harrison Avenue, Suite 606, Boston, MA 02118, USA.
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Rossi P, Lolicato F, Grimaldi P, Dolci S, Di Sauro A, Filipponi D, Geremia R. Transcriptome analysis of differentiating spermatogonia stimulated with kit ligand. Gene Expr Patterns 2007; 8:58-70. [PMID: 18036996 DOI: 10.1016/j.modgep.2007.10.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 10/02/2007] [Accepted: 10/17/2007] [Indexed: 01/15/2023]
Abstract
Kit ligand (KL) is a survival factor and a mitogenic stimulus for differentiating spermatogonia. However, it is not known whether KL also plays a role in the differentiative events that lead to meiotic entry of these cells. We performed a wide genome analysis of difference in gene expression induced by treatment with KL of spermatogonia from 7-day-old mice, using gene chips spanning the whole mouse genome. The analysis revealed that the pattern of RNA expression induced by KL is compatible with the qualitative changes of the cell cycle that occur during the subsequent cell divisions in type A and B spermatogonia, i.e. the progressive lengthening of the S phase and the shortening of the G2/M transition. Moreover, KL up-regulates in differentiating spermatogonia the expression of early meiotic genes (for instance: Lhx8, Nek1, Rnf141, Xrcc3, Tpo1, Tbca, Xrcc2, Mesp1, Phf7, Rtel1), whereas it down-regulates typical spermatogonial markers (for instance: Pole, Ptgs2, Zfpm2, Egr2, Egr3, Gsk3b, Hnrpa1, Fst, Ptch2). Since KL modifies the expression of several genes known to be up-regulated or down-regulated in spermatogonia during the transition from the mitotic to the meiotic cell cycle, these results are consistent with a role of the KL/kit interaction in the induction of their meiotic differentiation.
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Affiliation(s)
- Pellegrino Rossi
- Dipartimento di Sanita' Pubblica e Biologia Cellulare, Universita' degli Studi di Roma Tor Vergata, via Montpellier 1, 00133 Rome, Italy.
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13
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Erin N, Zhao W, Bylander J, Chase G, Clawson G. Capsaicin-induced inactivation of sensory neurons promotes a more aggressive gene expression phenotype in breast cancer cells. Breast Cancer Res Treat 2006; 99:351-64. [PMID: 16583263 DOI: 10.1007/s10549-006-9219-7] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 07/12/2005] [Indexed: 12/25/2022]
Abstract
Capsaicin-induced inactivation of sensory neurons has been reported to enhance metastasis of a murine breast cancer cell line, specifically enhancing myocardial metastases. Here we characterized changes in gene expression patterns in primary tumors which developed in capsaicin-treated vs. control mice. We identified a small cohort of genes (17) which all showed significant decreases in expression levels. All of the identified genes have been linked to cell growth, differentiation, and/or cancer progression. Three representative genes, Caspase-7 (an executor of apoptosis), ADAM-10 (A Disintegrin and Metalloprotease), and Elk-3 (a transcriptional repressor of the ternary factor subfamily of the Ets factors) were further investigated. All three showed dramatic downregulation at the protein level in primary tumors from capsaicin-treated animals compared with control (vehicle-treated) animals, and their expression was also lost in cell culture. Elk-3 and Caspase-7 were not expressed in vitro in cultured cell lines, suggesting that their expression was induced by the tumor microenvironment. Loss of Caspase-7 expression can be expected to result in loss of function of apoptotic pathways. At first glance, loss of ADAM-10 expression would be expected to result in decreased invasive capability, due to loss of matrix metalloprotease activity. However, just the opposite appears to be true. We found that ADAM-10 actually hydrolyzes Substance P. Specifically ADAM-10 produces the same growth-inhibitory products from Substance P (i.e., SP (1-7)) that Neprilysin does, so that loss of ADAM-10 expression actually results in loss of production of growth inhibitory peptides from Substance P. Similarly, ADAM-10 also efficiently hydrolyzes Calcitonin Gene-Related Peptide, which may act in concert with Substance P. Finally, overactivity of Ets transcriptional suppressor functions has been linked to inhibition of tumorigenesis (e.g., Erf and Mef), and in addition loss of Elk-3 expression might also be be linked to tumorigenesis via loss of its putative anti-inflammatory activities. There is anecdotal evidence in the literature to indicate that the rest of the down-regulated genes may also contribute to development of a more aggressive phenotype in this breast cancer model.
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Affiliation(s)
- Nuray Erin
- Department of Pathology, Gittlen Cancer Research Foundation, Hershey Medical Center, H059, Pennsylvania State University, 500 University drive, Hershey, PA 17033, USA
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14
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Johnstone O, Deuring R, Bock R, Linder P, Fuller MT, Lasko P. Belle is a Drosophila DEAD-box protein required for viability and in the germ line. Dev Biol 2005; 277:92-101. [PMID: 15572142 DOI: 10.1016/j.ydbio.2004.09.009] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2004] [Revised: 09/03/2004] [Accepted: 09/07/2004] [Indexed: 10/26/2022]
Abstract
DEAD-box proteins are ATP-dependent RNA helicases that function in various stages of RNA processing and in RNP remodeling. Here, we report identification and characterization of the Drosophila protein Belle (Bel), which belongs to a highly conserved subfamily of DEAD-box proteins including yeast Ded1p, Xenopus An3, mouse PL10, human DDX3/DBX, and human DBY. Mutations in DBY are a frequent cause of male infertility in humans. Bel can substitute in vivo for Ded1p, an essential yeast translation factor, suggesting a requirement for Bel in translation initiation. Consistent with an essential cellular function, strong loss of function mutations in bel are recessive lethal with a larval growth defect phenotype. Hypomorphic bel mutants are male-sterile. Bel is also closely related to the Drosophila DEAD-box protein Vasa (Vas), a germ line-specific translational regulator. We find that Bel and Vas colocalize in nuage and at the oocyte posterior during oogenesis, and that bel function is required for female fertility. However, unlike Vas, Bel is not specifically enriched in embryonic pole cells. We conclude that the DEAD-box protein Bel has evolutionarily conserved roles in fertility and development.
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Affiliation(s)
- Oona Johnstone
- Department of Biology, McGill University, Montréal, Québec, Canada H3A 1B1
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15
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Abstract
Post-transcriptional mechanisms play an important role in the biology of germ cells, where they control key developmental decisions in cell division, differentiation and death. Because these post-transcriptional controls are cell-type-specific, and often utilize germ-cell-specific RNA-binding proteins, they provide useful diagnostic markers for male infertility and testicular cancer. Investigation of the genetics of male infertility in men and model organisms suggests that disruption of post-transcriptional control mechanisms can cause specific germ cell pathologies, and these studies point to future possible therapeutic routes for restoring spermatogenesis.
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Affiliation(s)
- Ingrid Ehrmann
- Institute of Human Genetics, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK
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16
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Vogt PH. Azoospermia factor (AZF) in Yq11: towards a molecular understanding of its function for human male fertility and spermatogenesis. Reprod Biomed Online 2005; 10:81-93. [PMID: 15705299 DOI: 10.1016/s1472-6483(10)60807-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Y chromosomal azoospermia factor (AZF) is essential for human spermatogenesis. It has been mapped by molecular deletion analyses to three subintervals in Yq11, AZFa, AZFb, and AZFc, containing a number of genes of which at least some control, post-transcriptionally, the RNA metabolism of other spermatogenesis genes, functionally expressed at different phases of the spermatogenic cycle. Intrachromosomal recombination events between homologous large repetitive sequence block in Yq11 are now recognized as the major cause of the AZFa, AZFb and AZFc microdeletions, and an overlap of the AZFb and AZFc regions was revealed by sequence analysis of the complete Yq11 region. The increasing knowledge of the expression patterns of AZF genes in human germ cells suggests that the DBY gene is the major AZFa gene, the RBMY gene the major AZFb gene, although a functional expression of the other AZFa/b genes in the male germ line is also most likely. Genetic redundancy might exist in AZFc because a number of gene copies in the large P1 palindrome structure in distal AZFc were found to be deleted also in fertile men.
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Affiliation(s)
- Peter H Vogt
- Section of Molecular Genetics and Infertility, Department of Gynecological Endocrinology and Reproductive Medicine, University of Heidelberg, Heidelberg, Germany.
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