Mouse homologues of the human AZF candidate gene RBM are expressed in spermatogonia and spermatids, and map to a Y chromosome deletion interval associated with a high incidence of sperm abnormalities (original) (raw)
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An RBM homologue maps to the mouse Y chromosome and is expressed in germ cells
Human Molecular Genetics, 1996
We have isolated a murine homologue of the human Y-linked RBM genes (previously termed YRRM), a gene family implicated in spermatogenesis and which encodes proteins containing an RNA recognition motif. A number of very similar copies of this gene (called Rbm) are present in the mouse. These mouse homologues are also Y-encoded, mapping on the short arm of the chromosome, proximal to Sry. Expression is confined to the testis, specifically the germ line on the basis of lack of expression in the germ-line negative testes of adult sex-reversed mice. The timing of Rbm transcription is regulated, with fetal message levels reaching a peak at 15 d.p.c. Transcripts are clearly detectable by 4 days after birth and reach their highest level at 14 d.p.p. which is the time at which the Y chromosome condenses during meiotic prophase. These results suggest that Rbm is functionally involved in germline RNA metabolism.
Cellular ontogeny of RBMY during human spermatogenesis and its role in sperm motility
Journal of Biosciences, 2013
The Y-chromosome-encoded gene RBMY (RNA-binding motif on Y) is a male germline RNA-binding protein and is postulated to be a RNA-splicing regulator. In order to understand the roles of RBMY in different stages of male gamete maturation, the present study aimed at determining its cellular expression during spermatogenesis, spermeogenesis and in mature spermatozoa. In the spermatogonia (cKIT-positive cells), RBMY immunolocalized as two distinct foci, one in the nucleolus and the other in the subnuclear region; in the spermatocytes (cKIT-negative cells), the nucleus had punctuate staining with a subnuclear foci; in the pachytene cells, the protein was localized as a punctuate pattern in the nucleus spread along the elongating chromosomes. In the round and the elongating spermatids, the protein expression was polarized and restricted to the cytoplasm and in the developing mid-piece. In testicular and ejaculated sperm, RBMY was localized to the mid-piece region and weakly in the tail. Incubation of spermatozoa with the RBMY antibody reduced its motility. The spatial differences in expression of RBMY in the germ cells and the presences of this protein in post-meiotic cells and in transcriptionally inert spermatozoa suggest its involvement in multiple functions beyond RNA splicing. One such possible function of RBMY could be its involvement in sperm motility.
International Journal of Andrology, 2001
Recent studies have indicated that at least three regions (AZF a±c) on the long arm of the Y-chromosome code for factors are involved in spermatogenesis. One of the candidate genes in the AZFb region is RBM1a, coding for a protein with an RNA binding motif. In this study, poly clonal antibodies raised against a 15 amino acid peptide, corresponding to residues 263±304 of the deduced amino acid sequence of RBM1a, has been used to localize the RBM1a protein in the human testis. Immunohistochemistry on normal human testis using this RBM1a antibody, localized the antigen to the nuclei of spermatogonia, primary spermatocytes, and round spermatids but not to the nuclei of elongated spermatids. The antibody also speci®cally identi®ed the nuclei of Sertoli cells, although the¯uorescence was not as strong as in the germ cell nuclei it identi®ed. No speci®c¯uorescence was seen in the nuclei of either peritubular, endothelial or Leydig cells. Western blot of normal human testicular tissue using the anti-RBM1a antibody gave rise to a single speci®c band of approximately 55 kDa, corresponding to the expected size of RBM1a. In view of its expression in germ cells, and because RBM1a has an RNA binding domain, RBM1a may be involved in RNA processing, such as RNA splicing or RNA export which are events necessary for normal spermatogenesis.
Human Reproduction, 1999
Microdeletions in Yq11 overlapping three distinct 'azoospermia factors' (AZFa-c) represent the aetiological factor of 10-15% of idiopathic azoospermia and severe oligozoospermia, with higher prevalence in more severe testiculopathies, such as Sertoli cell-only syndrome. Using a PCR-based screening, we analysed Yq microdeletions in 180 infertile patients affected by idiopathic Sertoli cell-only syndrome and different degrees of hypospermatogenesis, compared with 50 patients with known causes of testicular alteration, 30 with obstructive azoospermia, and 100 normal fertile men. In idiopathic severe testiculopathies (Sertoli cell-only syndrome and severe hypospermatogenesis), a high prevalence of microdeletions (34.5% and 24.7% respectively) was found, while milder forms were not associated with Yq alteration. No deletions were found in testiculopathies of known aetiology, obstructive azoospermia, normal fertile men and male relatives of patients with deletions. Deletions in the AZFc region involving the DAZ gene were the most frequent finding and they were more often observed in severe hypospermatogenesis than in Sertoli cell-only syndrome, suggesting that deletions of this region are not sufficient to cause complete loss of the spermatogenic line. Deletions in AZFb involving the RBM gene were less frequently detected and there was no correlation with testicular phenotype, with an apparent minor role for such gene in spermatogenesis. The DFFRY gene was absent in a fraction of patients, making it a candidate AZFa gene. Our data suggest that larger deletions involving more than one AZF-candidate gene are associated with a more severe testicular phenotype.
Spam1 (PH20) mutations and sperm dysfunction in mice with the Rb(6.16) or Rb(6.15) translocation
Mammalian Genome, 2001
In mice bearing the Rb(6.16) or Rb(6.15) Robertsonian translocation (Rb), sperm dysfunction associated with the Rbs has been shown to lead to transmission ratio distortions (TRDs) in heterozygotes. The severity of the TRDs is directly related to the severity in the alteration of expression of the gene for the Sperm Adhesion Molecule 1 (Spam1), which maps to proximal mouse Chromosome 6 (Chr 6) near the translocation junction and encodes a sperm antigen with hyaluronidase activity. Here we demonstrate that there is a significantly reduced fertility in the Rb homozygotes (P P Spam1 locus, 11 point mutations are scattered in the 5′ and 3′ UTRs and the coding region, where one leads to the replacement of a conserved residue. Entrapment of spontaneous Spam1 mutations, owing to recombination suppression near the Rb junctions, is proposed as the major underlying defect of the sperm dysfunction.
Human Reproduction, 2004
BACKGROUND: Partial deletions of the AZFc region of the Y chromosome were reported to be a significant risk factor for oligo-/azoospermia. In this study, we assessed the occurrence and frequency of partial AZFc microdeletions in patients with spermatogenic failure and in controls with normal spermatogenesis. METHODS: In a retrospective study design, gr/gr, b1/b3 and b2/b3 deletions were analysed by multiplex PCR in 170 men with normal spermatogenesis and 348 men with non-obstructive oligo-/azoospermia. RESULTS: gr/gr deletions were found in 14 men with oligozoospermia or azoospermia (4.0%) and in three normozoospermic men (1.8%) (NS). b1/b3 deletions were found both in controls (n 5 1) and in patients (n 5 1). b2/b3 deletions were significantly more frequent in the normozoospermic (five out of 170) than in the oligo-/azoospermic men (two out of 348). Three novel partial AZFc deletion patterns were found in four oligo-/azoospermic men. No correlation with semen or other clinical parameters was found. CONCLUSIONS: The frequency of gr/gr deletions is not significantly increased in men with oligo-/azoospermia, indicating that they are not sufficient per se to cause spermatogenetic impairment and infertility. b1/b3 and b2/b3 deletions are probably irrelevant for spermatogenesis. Novel deletion patterns found exclusively in infertile men suggest that other, still unexplored partial deletions might contribute to spermatogenic failure.
Nature Genetics, 1995
We have detected deletions of portions of the Y chromosome long arm hi 12 of 89 men with azoospermia (no spermatozoa hi their semen). No Y deletions were detected hi their male relatives or in 90 other fertile males. The 12 deletions overlap, denning a region likely to contain one or more genes required for spermatogenesis (the azoospermia factor, AZF). Deletion of the AZF region is associated with highly variable testicular defects, ranging from the complete absence of germ cells to spermatogenic arrest with the occasional production of condensed spermatids. We found no evidence of YRRM genes, recently proposed as AZF candidates hi the AZF region. The region contains a single-copy gene, DAZ (deleted in azoospermia), which is transcribed in the adult testis and appears to encode an RNAbinding protein. The possibility that DAZ is AZF should now be explored.
Influence of partial deletion of the Y chromosome on mouse sperm phenotype
Reproduction, 1991
Two congenic strains of mice (control, B10.BR/SgSn; mutant, B10.BR\x=req-\ Ydel/Ms with partial deletion of the Y chromosome) were examined. In control males, 22\m=.\6%of spermatozoa had abnormal heads; in mutant males, there were 64\m=.\2%, the most common being heads with flat acrosomes. Sodium dodecyl sulphate polyacrylamide gel electrophoresis of mature sperm proteins, followed by acrosin assay and acrosome silver staining, revealed a reduced concentration of acrosin in acrosomal caps in 35\m=.\8%of the spermatozoa in mutant males. Electron microscope analysis showed that some of the round, early spermatids in the mutants had normally formed acrosomal caps but lacked the proacrosomal granule and had no, or only scarce, acrosomal material. These observations indicate that formation of the acrosomal cap is controlled separately from the synthesis of the acrosomal material and suggest that some factors linked on the Y chromosome are involved in the control of acrosome development.
Rbm46, a novel germ cell-specific factor, modulates meiotic progression and spermatogenesis
Biology of Reproduction, 2021
It has been suggested that many novel RNA-binding proteins (RBPs) are required for gametogenesis, but the necessity of few of these proteins has been functionally verified. Here, we identified one RBP, Rbm46, and investigated its expression pattern and role in zebrafish reproduction. We found that rbm46 is maternally provided and specifically expressed in the germ cells of gonadal tissues using in situ hybridization, reverse transcription-PCR, and quantitative real-time polymerase chain reaction (qRT-PCR). Two independent rbm46 mutant zebrafish lines were generated via the transcription activator-like effector nuclease technique. Specific disruption of rbm46 resulted in masculinization and infertility in the mutants. Although the spermatogonia appeared grossly normal in the mutants, spermatogenesis was impaired, and meiosis events were not observed. The introduction of a tp53M214K mutation could not rescue the female-to-male sex-reversal phenotype, indicating that rbm46 acts indepen...
Biology of Reproduction, 2022
Using mice with Y chromosome deficiencies and supplementing Zfy transgenes, we, and others, have previously shown that the loss of Y chromosome Zfy1 and Zfy2 genes is associated with infertility and spermiogenic defects and that the addition of Zfy transgenes rescues these defects. In these past studies, the absence of Zfy was linked to the loss of other Y chromosome genes, which might have contributed to spermiogenic phenotypes. Here, we used CRISPR/Cas9 to specifically remove open reading frame of Zfy1, Zfy2, or both Zfy1 and Zfy2, and generated Zfy knockout (KO) and double knockout (DKO) mice. Zfy1 KO and Zfy2 KO mice were both fertile, but the latter had decreased litters size and sperm number, and sperm headshape abnormalities. Zfy DKO males were infertile and displayed severe spermatogenesis defects. Postmeiotic arrest largely prevented production of sperm and the few sperm that were produced all displayed gross headshape abnormalities and structural defects within head and tail. Infertility of Zfy DKO mice could be overcome by injection of spermatids or sperm directly to oocytes, and the resulting male offspring had the same spermiogenic phenotype as their fathers. The study is the first describing detailed phenotypic characterization of mice with the complete Zfy gene loss. It provides evidence supporting that the presence of at least one Zfy homolog is essential for male fertility and development of normal sperm functional in unassisted fertilization. The data also show that while the loss of Zfy1 is benign, the loss of Zfy2 is mildly detrimental for spermatogenesis.