Juvenile Spermatogonial Depletion (jsd): A Genetic Defect of Germ Cell Proliferation of Male Mice1

Beamer, Wesley G.; Cunliffe-Beamer, Terrie L.; Shultz, Kathryn L.; Langley, Stephen H.; Roderick, Thomas H.

doi:10.1095/biolreprod38.4.899

Cited by 97 publications

(54 citation statements)

References 23 publications

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“…To determine which type of cells in testis expressed AZ1, Northern-blot analysis of RNA from testis of the jsdljsd mutant mouse, which has a defect in germ cell maturation and the seminiferous tubules of which contain spermatocytes arrested at an early stage of spermatogenesis [39], was performed. As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Isolation of a Novel cDNA that Encodes a Protein Localized to the Pre‐Acrosome Region of Spermatids

Aoto

Tsuchida

Nishina

et al. 1995

European Journal of Biochemistry

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We have identified a novel cDNA clone, named AZI, obtained from a cDNA library of mRNA prepared from C3H10T1/2 cells that had been transiently exposed to 5-azacytidine, a potent demethylating reagent. The amount of transcript increased with 5-azacytidine treiltment of C3H10T1/2 cells and the transcript was highly expressed in mouse testis. As the mutant mouse jsdljsd, which has a defect in germ cell maturation, barely expressed the transcript, the message was expected to be expressed specifically in spermatocytes. The mRNA was detected at significant levels in the testes from mice aged 16 days after birth, suggesting that its expression started at the pachytene spermatocyte stage. The elucidated nucleotide sequence contained a 2841 -nucleotide open reading frame, and the expected amino acid sequence had a molecular mass of 107 254 Da. Specific antibodies raised against the fusion protein including glutathione S-transferase revealed an approximately 130-kDa band of a translation product in testis and in cultured cells transfected with AZ1 cDNA in the expression vector on Western-blot analysis. The protein was localized to the pre-acrosome region of round and elongated spermatids. However, it was not detected at a more advanced stage of spermatids, i.e. just before their release from Sertoli cells. This protein may play an important role in spermatogenesis.Keywords: DNA demethylation ; spermatogensis ; acrosome ; cDNA cloning.The expression of mammalian genes is often correlated with the methylation state of the CpG sequences in their promoter regions [l]. The promoter regions of house-keeping genes are undermethylated in all cells. In contrast, tissue-specific genes are usually methylated at the 5 position of cytosine in the CpG sequences, except in the tissues in which they are expressed [ 21. Transient exposure of mouse C3H1 OT1/2 cells to 5-azacytidine, a cytosine analogue that cannot be methylated at the 5 position and which is also a potent inhibitor of DNA methyltransferase [3], causes the cells to differentiate into chondrocytes, adipocytes, and myotubes [4], or to undergo transformation [ S ] . The underlying cause of these changes in phenotype is the induction of the genes regulating the phenotype through undermethylation of the genes, such as the myoDl gene for myotubes 161 and endogenous retroviral genes for transformation IS]. One of the possible important roles of DNA methylation in germ cells is the marking of specific genes to determine if they should be expressed at an early stage of embryogenesis. This is called parental or genomic imprinting [7]. At the same time, many tissuespecific genes should be expressed during oogenesis or sperma- University, 3-2, Yamadaoka, Suita, Osaka, Japan 565 togenesis, as these cells are very specialized. In particular, male germ cells undergo drastic differentiation during spermatogenesis. Recently, many genes have been reported to be transcribed post-meiotically in animal male gametes [8, 91. Among these, the expression of the phosphoglycerate kinase 2 gene and t...

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Section: Resultsmentioning

confidence: 99%

Isolation of a Novel cDNA that Encodes a Protein Localized to the Pre‐Acrosome Region of Spermatids

Aoto

Tsuchida

Nishina

et al. 1995

European Journal of Biochemistry

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“…A mouse mutation, juvenile spermatogo nia depletion [isd], throws some light on these questions. In the homozygous jsd mutants, the first wave of sper matogenesis takes place, but spermatogenesis fails to be maintained, leading to germ-cell degeneration after midpuberty and sterility (Beamer et al 1988;Barton et al 1989;Mizunuma et al 1992). This seems to indicate that the initiation and maintenance of spermatogenesis are controlled by different mechanisms.…”

Section: Discussionmentioning

confidence: 99%

The gene encoding bone morphogenetic protein 8B is required for the initiation and maintenance of spermatogenesis in the mouse.

Zhao¹,

Deng²,

Labosky³

et al. 1996

Genes Dev.

242

114

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Bone morphogenetic protein 8B (BMP8B) is a member of the TGFp superfamily of growth factors. In the mouse, Bmp8b is expressed in male germ cells of the testis and trophoblast cells of the placenta, suggesting that it has a role in spermatogenesis and reproduction. To investigate these possibilities, we have generated mice with a targeted mutation in Bmp8b. Here, we show that homozygous BmpSb^^^"' mutant males exhibit variable degrees of germ-cell deficiency and infertility. Detailed analysis reveals two separable defects in the homozygous mutant testes. First, during early puberty (2 weeks old or younger) the germ cells of all homozygous mutants either fail to proliferate or show a marked reduction in proliferation and a delayed differentiation. Second, in adults, there is a significant increase in programmed cell death (apoptosis) of spermatocytes, leading to germ-cell depletion and sterility. Sertoli cells and Leydig cells appear relatively unaffected in mutants. This study therefore provides the first genetic evidence that a murine germ cell-produced factor, BMP8B, is required for the resumption of male germ-cell proliferation in early puberty, and for germ-cell survival and fertility in the adult.

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“…One attempt to understand the morphological events of spermatogenesis at the molecular level has been to study testicular expression of genes required for spermatogenesis . For this, the availability of mutant strains of mice [9,20,21], experimentally induced cryptorchidism and orchidopexy or surgical reversal [22], age-dependent progression of germ cell differentiation in juvenile testes [23] and cell-separation techniques [24,25], made the studying of the mouse spermatogenesis system particularly amenable to biochemical and molecular analyses. By using the various techniques and methods, the specific expression of some genes has been observed in testes, and some interesting information has been obtained by the isolation of cDNA clones specifically expressed in testes [3].…”

Section: Discussionmentioning

confidence: 99%

Isolation and characterization of cDNA clones specifically expressed in testicular germ cells

et al. 1994

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We have cloned cDNAs involved in germ cell-specific expression. For this, a subtracted cDNA library was generated by subtracting cDNAs derived from supporting cells of mutant testis from wild-type testis cDNAs. Detailed analyses of mRNA expression revealed that the genes corresponding to the cloned cDNAs were exclusively expressed in testes and were developmentally controlled.Key words: Testis; Mouse; Protamin; cDNA library; Subtraction; WnV mutant; Actin capping protein IntillctlonMouse spermatogenesis is an excellent model system to study regulation of gene expression during differentiation. Postnatal development of the mouse seminiferous epithelium is a complicated process which finally generates a tissue able to produce functional spermatozoa. The whole process can be subdivided into three parts: (i) a premeiotic phase characterized by an increase in cell number due to mitotic divisions of diploid spermatogonia; (ii) a meiotic prophase, which leads to the formation of haploid round spermatids; and (iii) a post-meiotic phase, which includes the morphogenetic events required for spermatozoa formation (spermiogenesis) [ 1,2]. Specific cells derived from the stem cells in seminiferous epithelium of the adult testis undergo these processes and continuously provide the mature sperms. The precise regulation of such germ cell differentiation requires a strict program of stage-and cell-specific gene expression in germ cells as well as in surrounding somatic cell types [3]. To understand the mechanism of testicular germ cell differentiation, it is of great interest to isolate specific genes and characterize their functions as well as their regulation. Materials and methods Preparation of cDNA libraries carrying directional insertsTotal RNA followed by purification of poly (A)+ RNA was extracted by the guanidme thiocyanate/CsTFA method from the testes of adult wild-type B6 mice and 4-month-old W/W" mutant mice [4]. Their cDNA libraries were prepared as described by Gubler and Hoffmann with some modifications (Kobori et al., manuscript in preparation) [5]. Briefly, cDNA was synthesized in a reaction mixture including 'MedCTP with reverse. transcriptase (Superscript II) from 2-5 pg of mouse testis poly(A)+ RNA and 1.6 pug of oligo (dT) primer carrying a Not1 site. The reaction mixture was treated with RNase H, followed by reaction with DNA polymerase I. Each end was blunt-ended with T4 DNA polymerase and ligated to an unphosphorylated BglII-SmaI adaptor. After digestion with NotI, small DNA fragments of less than 300 bp were removed by a CROMA spin-400 column (Clontech, USA). The cDNA fragments were directionally inserted between the Not1 (dephosphorylated) and BgZII sites of vector pAP3neo (H. Nojima, unpublished). The ligation mixture was electroporated into MC1061A cells as described [q. The complexities of the cDNA libraries used here *Corresponding author. Fax: (81) (6) 879-8339.were 6.0 x lo6 colony forming units (cfu) for the B6 wild-type mouse and 2.8 x lo6 cfu for the Wm mutant mouse. Preparation of a s...

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Juvenile Spermatogonial Depletion (jsd): A Genetic Defect of Germ Cell Proliferation of Male Mice1

Cited by 97 publications

References 23 publications

Isolation of a Novel cDNA that Encodes a Protein Localized to the Pre‐Acrosome Region of Spermatids

Isolation of a Novel cDNA that Encodes a Protein Localized to the Pre‐Acrosome Region of Spermatids

The gene encoding bone morphogenetic protein 8B is required for the initiation and maintenance of spermatogenesis in the mouse.

Isolation and characterization of cDNA clones specifically expressed in testicular germ cells

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