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Kulathinal R, Singh RS. CYTOLOGICAL CHARACTERIZATION OF PREMEIOTIC VERSUS POSTMEIOTIC DEFECTS PRODUCING HYBRID MALE STERILITY AMONG SIBLING SPECIES OF THE DROSOPHILA MELANOGASTER COMPLEX. Evolution 2017; 52:1067-1079. [PMID: 28565214 DOI: 10.1111/j.1558-5646.1998.tb01834.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/1997] [Accepted: 03/24/1998] [Indexed: 11/29/2022]
Abstract
In accordance with Haldane's rule, hybridizations between species of the Drosophila simulans clade produce fertile females but sterile males. In this study, a comprehensive characterization was undertaken on the six types of F1 males that were the result of the crosses between D. simulans, D. sechellia, and D. mauritiana. With the use of light and electron microscopy, it was shown that while each particular hybrid genotype exhibited a specific sterility phenotype, these phenotypes fell into two distinct classes. The two hybrid genotypes that possessed D. mauritiana X-chromosomes contained spermatogenic defects that caused arrests in premeiotic spermatogenic stages. The other four F1 hybrids possessed postmeiotic spermatogenic defects. Nonsynchronous cell divisions, underdeveloped mitochondrial derivative-axonemal associations, and microtubule abnormalities were common to all of these hybrids. Each particular postmeiotically defective hybrid genotype demonstrated characteristically distinct profiles in sperm bundle number in addition to characteristic spermiogenic arrests in the furthest developed spermatids. These results in species hybrids contrast with the absence of significant differences in spermatogenic characters between species of this clade. In addition, by utilizing an attached-X cross, we investigated the influence of maternal effects and cytoplasmic factors on the sterility of D. simulans F1 hybrids and found none. However, we discovered a strain of D. simulans (2119) that caused a large shift in sterility from postmeiotic to premeiotic when crossed to D. sechellia. This suggests that D. simulans is polymorphic for genes involving premeiotic and postmeiotic sterility and that the two types of sterilities between species may have a simple genetic basis.
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Affiliation(s)
- Rob Kulathinal
- Department of Biology, McMaster University, Hamilton, Ontario, L8S 4K1, Canada
| | - Rama S Singh
- Department of Biology, McMaster University, Hamilton, Ontario, L8S 4K1, Canada
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2
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Chatterjee N, Rollins J, Mahowald AP, Bazinet C. Neurotransmitter Transporter-Like: a male germline-specific SLC6 transporter required for Drosophila spermiogenesis. PLoS One 2011; 6:e16275. [PMID: 21298005 PMCID: PMC3029318 DOI: 10.1371/journal.pone.0016275] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 12/13/2010] [Indexed: 02/03/2023] Open
Abstract
The SLC6 class of membrane transporters, known primarily as neurotransmitter transporters, is increasingly appreciated for its roles in nutritional uptake of amino acids and other developmentally specific functions. A Drosophila SLC6 gene, Neurotransmitter transporter-like (Ntl), is expressed only in the male germline. Mobilization of a transposon inserted near the 3' end of the Ntl coding region yields male-sterile mutants defining a single complementation group. Germline transformation with Ntl cDNAs under control of male germline-specific control elements restores Ntl/Ntl homozygotes to normal fertility, indicating that Ntl is required only in the germ cells. In mutant males, sperm morphogenesis appears normal, with elongated, individualized and coiled spermiogenic cysts accumulating at the base of the testes. However, no sperm are transferred to the seminal vesicle. The level of polyglycylation of Ntl mutant sperm tubulin appears to be significantly lower than that of wild type controls. Glycine transporters are the most closely related SLC6 transporters to Ntl, suggesting that Ntl functions as a glycine transporter in developing sperm, where augmentation of the cytosolic pool of glycine may be required for the polyglycylation of the massive amounts of tubulin in the fly's giant sperm. The male-sterile phenotype of Ntl mutants may provide a powerful genetic system for studying the function of an SLC6 transporter family in a model organism.
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Affiliation(s)
- Nabanita Chatterjee
- Department of Biological Sciences, St. John's University, Jamaica, New York, United States of America
| | - Janet Rollins
- Department of Biological Sciences, St. John's University, Jamaica, New York, United States of America
| | - Anthony P. Mahowald
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, United States of America
| | - Christopher Bazinet
- Department of Biological Sciences, St. John's University, Jamaica, New York, United States of America
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3
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Piergentili R. Evolutionary conservation of lampbrush-like loops in drosophilids. BMC Cell Biol 2007; 8:35. [PMID: 17697358 PMCID: PMC1978495 DOI: 10.1186/1471-2121-8-35] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 08/14/2007] [Indexed: 12/02/2022] Open
Abstract
Background Loopin-1 is an abundant, male germ line specific protein of Drosophila melanogaster. The polyclonal antibody T53-F1 specifically recognizes Loopin-1 and enables its visualization on the Y-chromosome lampbrush-like loop named kl-3 during primary spermatocyte development, as well as on sperm tails. In order to test lampbrush-like loop evolutionary conservation, extensive phase-contrast microscopy and immunostaining with T53-F1 antibody was performed in other drosophilids scattered along their genealogical tree. Results In the male germ line of all species tested there are cells showing giant nuclei and intranuclear structures similar to those of Drosophila melanogaster primary spermatocytes. Moreover, the antibody T53-F1 recognizes intranuclear structures in primary spermatocytes of all drosophilids analyzed. Interestingly, the extent and conformation of the staining pattern is species-specific. In addition, the intense staining of sperm tails in all species suggests that the terminal localization of Loopin-1 and its orthologues is conserved. A comparison of these cytological data and the data coming from the literature about sperm length, amount of sperm tail entering the egg during fertilization, shape and extent of both loops and primary spermatocyte nuclei, seems to exclude direct relationships among these parameters. Conclusion Taken together, the data reported strongly suggest that lampbrush-like loops are a conserved feature of primary spermatocyte nuclei in many, if not all, drosophilids. Moreover, the conserved pattern of the T53-F1 immunostaining indicates that a Loopin-1-like protein is present in all the species analyzed, whose localization on lampbrush-like loops and sperm tails during spermatogenesis is evolutionary conserved.
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Affiliation(s)
- Roberto Piergentili
- Dipartimento di Genetica e Biologia Molecolare, Sapienza Università di Roma, Piazzale Aldo Moro 5, 00185 Rome, Italy.
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Riparbelli MG, Callaini G. The Drosophila parkin homologue is required for normal mitochondrial dynamics during spermiogenesis. Dev Biol 2006; 303:108-20. [PMID: 17123504 DOI: 10.1016/j.ydbio.2006.10.038] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 10/20/2006] [Accepted: 10/26/2006] [Indexed: 11/28/2022]
Abstract
Drosophila parkin, the ortholog of the human parkin gene, responsible for a familiar form of autosomal recessive juvenile parkinsonism, has been shown previously to be involved in Drosophila male fertility. Loss-of-function mutations in the parkin gene cause failure of spermatid individualization by affecting the proper progression of the actin-based investment cones that assemble in the nuclear region, but fail to translocate in synchrony down the cyst. In parkin mutants, the investment cones are scattered along the post-elongated spermatid bundles and fail to act properly in the process of sperm individualization. Using phase-contrast and electron microscopy analysis, we demonstrate that the parkin spermatids assemble a seemingly normal onion-stage nebenkern, but when the axoneme elongates only one mitochondrial derivative unfurls from the nebenkern. This unique mitochondrial derivative undergoes abnormal shaping and condensation during spermatid elongation. Our results indicate that parkin gene function is necessary for mitochondrial morphogenesis during earlier and later phases of spermiogenesis. The failure of cyst individualization may be due to the sensitivity of investment cone movement to the perturbation of mitochondrial morphology during spermatid elongation.
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Sarkar S, Lakhotia SC. The Hsp60C gene in the 25F cytogenetic region in Drosophila melanogaster is essential for tracheal development and fertility. J Genet 2005; 84:265-81. [PMID: 16385159 DOI: 10.1007/bf02715797] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Earlier studies have shown that of the four genes (Hsp60A, Hsp60B, Hsp60C, Hsp60D genes) predicted to encode the conserved Hsp60 family chaperones in Drosophila melanogaster, the Hsp60A gene (at the 10A polytene region) is expressed in all cell types of the organism and is essential from early embryonic stages, while the Hsp60B gene (at 21D region) is expressed only in testis, being essential for sperm individualization. In the present study, we characterized the Hsp60C gene (at 25F region), which shows high sequence homology with the other three Hsp60 genes of D. melanogaster. In situ hybridization of Hsp60C-specific riboprobe shows that expression of this gene begins in late embryonic stages (stage 14 onwards), particularly in the developing tracheal system and salivary glands; during larval and adult stages, it is widely expressed in many cell types but much more strongly in tracheae and in developing and differentiating germ cells. A P-insertion mutant (Hsp60C(1)) allele with the P transposon inserted at -251 position of the Hsp60C gene promoter was generated. This early larval recessive lethal mutation significantly reduces levels of Hsp60C transcripts in developing tracheae and this is associated with a variety of defects in the tracheal system, including lack of liquid clearance. About 10% of the homozygotes survive as weak, shortlived and completely sterile adults. Testes of the surviving mutant males are significantly smaller, with fewer spermatocytes, most of which do not develop beyond the round spermatid stage. In situ and Northern hybridizations show significantly reduced levels of the Hsp60C transcripts in Hsp60C(1) homozygous adult males. The absence of early meiotic stages in the Hsp60C(1) homozygous testes contrasts with the effect of testis-specific Hsp60B (21D) gene, whose mutation affects individualization of sperm bundles later in spermiogenesis. In view of the specific effects in tracheal development and in early stages of spermatogenesis, it is likely that, besides its functions as a chaperone, Hsp60C may have signalling functions and may also be involved in cation transport across the developing tracheal epithelial cells.
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Affiliation(s)
- Surajit Sarkar
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India
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6
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Hackstein JH, Hochstenbach R, Pearson PL. Towards an understanding of the genetics of human male infertility: lessons from flies. Trends Genet 2000; 16:565-72. [PMID: 11102707 DOI: 10.1016/s0168-9525(00)02140-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
It has been argued that about 4-5% of male adults suffer from infertility due to a genetic causation. From studies in the fruitfly Drosophila, there is evidence that up to 1500 recessive genes contribute to male fertility in that species. Here we suggest that the control of human male fertility is of at least comparable genetic complexity. However, because of small family size, conventional positional cloning methods for identifying human genes will have little impact on the dissection of male infertility. A critical selection of well-defined infertility phenotypes in model organisms, combined with identification of the genes involved and their orthologues in man, might reveal the genes that contribute to human male infertility.
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Affiliation(s)
- J H Hackstein
- Dept of Evolutionary Microbiology, University of Nijmegen, Toernooiveld 1, NL-6525 ED Nijmegen, The Netherlands.
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Matsushita T, Fujii-Taira I, Tanaka Y, Homma KJ, Natori S. Male-specific IDGF, a novel gene encoding a membrane-bound extracellular signaling molecule expressed exclusively in testis of Drosophila melanogaster. J Biol Chem 2000; 275:36934-41. [PMID: 10967093 DOI: 10.1074/jbc.m003455200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We identified a novel gene of Drosophila melanogaster, Male-specific IDGF (MSI), encoding a transmembrane signaling molecule with exclusive expression in the testis. This molecule (MSI) contains a single transmembrane domain and has 35% amino acid identity with insect-derived growth factor (IDGF), a soluble growth factor for embryonic cells of the flesh fly, Sarcophaga peregrina. When MSI was exogenously expressed in Schneiders's line 2 cells, it was shown to be localized on the cell surface and exhibits growth factor activity, suggesting that MSI is a membrane-bound extracellular signaling molecule. Gene expression studies revealed that MSI mRNA was restricted to mature primary spermatocytes, whereas MSI was detected in the cells at the later developmental stages. Analysis using four meiotic arrest mutants, aly, can, mia, and sa suggested that MSI is involved in spermiogenesis, the final differentiation step of spermatogenesis. These results suggest that MSI is an extracellular signaling molecule participating in spermatogenesis and is a new member of the IDGF family.
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Affiliation(s)
- T Matsushita
- Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-0033, Japan
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8
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Orgad S, Rosenfeld G, Greenspan RJ, Segal D. courtless, the Drosophila UBC7 homolog, is involved in male courtship behavior and spermatogenesis. Genetics 2000; 155:1267-80. [PMID: 10880487 PMCID: PMC1461169 DOI: 10.1093/genetics/155.3.1267] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The courtless (col) mutation disrupts early steps of courtship behavior in Drosophila males, as well as the development of their sperm. Most of the homozygous col/col males (78%) do not court at all. Only 5% perform the entire ritual and copulate, yet these matings produce no progeny. The col gene maps to polytene chromosome band 47D. It encodes two proteins that differ in their carboxy termini and are the Drosophila homologs of the yeast ubiquitin-conjugating enzyme UBC7. The col mutation is caused by an insertion of a P element into the 3' UTR of the gene, which probably disrupts translational regulatory elements. As a consequence, the homozygous mutants exhibit a six- to sevenfold increase in the level of the COL protein. The col product is essential, and deletions that remove the col gene are lethal. During embryonic development col is expressed primarily in the CNS. Our results implicate the ubiquitin-mediated system in the development and function of the nervous system and in meiosis during spermatogenesis.
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Affiliation(s)
- S Orgad
- Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Tel-Aviv 69978, Israel
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9
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Timakov B, Zhang P. Genetic analysis of a Y-chromosome region that induces triplosterile phenotypes and is essential for spermatid individualization in Drosophila melanogaster. Genetics 2000; 155:179-89. [PMID: 10790393 PMCID: PMC1461087 DOI: 10.1093/genetics/155.1.179] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The heterochromatic Y chromosome of Drosophila melanogaster contains approximately 40 Mb of DNA but has only six loci mutable to male sterility. Region h1-h9 on YL, which carries the kl-3 and kl-5 loci, induces male sterility when present in three copies. We show that three separate segments within the region are responsible for the triplosterility and have an additive effect on male fertility. The triplosterile males displayed pleiotropic defects, beginning at early postmeiotic stages. However, the triplosterility was unaffected by kl-3 or kl-5 alleles. These data suggest that region h1-h9 is complex and may contain novel functions in addition to those of the previously identified kl-3 and kl-5 loci. The kl-3 and kl-5 mutations as well as deficiencies within region h1-h9 result in loss of the spermatid axonemal outer dynein arms. Examination using fluorescent probes showed that males deficient for h1-h3 or h4-h9 displayed a postmeiotic lesion with disrupted individualization complexes scattered along the spermatid bundle. In contrast, the kl-3 and kl-5 mutations had no effect on spermatid individualization despite the defect in the axonemes. These results demonstrate that region h1-h9 carries genetically separable functions: one required for spermatid individualization and the other essential for assembling the axonemal dynein arms.
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Affiliation(s)
- B Timakov
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269-2131, USA
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10
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Hochstenbach R, Hackstein JH. The comparative genetics of human spermatogenesis: clues from flies and other model organisms. Results Probl Cell Differ 2000; 28:271-98. [PMID: 10626302 DOI: 10.1007/978-3-540-48461-5_11] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- R Hochstenbach
- Department of Medical Genetics, University Medical Center, Utrecht, The Netherlands
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11
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Yue L, Karr TL, Nathan DF, Swift H, Srinivasan S, Lindquist S. Genetic analysis of viable Hsp90 alleles reveals a critical role in Drosophila spermatogenesis. Genetics 1999; 151:1065-79. [PMID: 10049923 PMCID: PMC1460532 DOI: 10.1093/genetics/151.3.1065] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Hsp90 chaperone protein maintains the activities of a remarkable variety of signal transducers, but its most critical functions in the context of the whole organism are unknown. Point mutations of Hsp83 (the Drosophila Hsp90 gene) obtained in two different screens are lethal as homozygotes. We report that eight transheterozygous mutant combinations produce viable adults. All exhibit the same developmental defects: sterile males and sterile or weakly fertile females. We also report that scratch, a previously identified male-sterile mutation, is an allele of Hsp82 with a P-element insertion in the intron that reduces expression. Thus, it is a simple reduction in Hsp90 function, rather than possible altered functions in the point mutants, that leads to male sterility. As shown by light and electron microscopy, all stages of spermatogenesis involving microtubule function are affected, from early mitotic divisions to later stages of sperm maturation, individualization, and motility. Aberrant microtubules are prominent in yeast cells carrying mutations in HSP82 (the yeast Hsp90 gene), confirming that Hsp90 function is connected to microtubule dynamics and that this connection is highly conserved. A small fraction of Hsp90 copurifies with taxol-stabilized microtubule proteins in Drosophila embryo extracts, but Hsp90 does not remain associated with microtubules through repeated temperature-induced assembly and disassembly reactions. If the spermatogenesis phenotypes are due to defects in microtubule dynamics, we suggest these are indirect, reflecting a role for Hsp90 in maintaining critical signal transduction pathways and microtubule effectors, rather than a direct role in the assembly and disassembly of microtubules themselves.
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Affiliation(s)
- L Yue
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA
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12
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Maside XR, Barral JP, Naveira HF. Hidden effects of X chromosome introgressions on spermatogenesis in Drosophila simulans x D. mauritiana hybrids unveiled by interactions among minor genetic factors. Genetics 1998; 150:745-54. [PMID: 9755205 PMCID: PMC1460339 DOI: 10.1093/genetics/150.2.745] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
One of the most frequent outcomes of interspecific hybridizations in Drosophila is hybrid male sterility. Genetic dissection of this reproductive barrier has revealed that the number of responsible factors is very high and that these factors are frequently engaged in complex epistatic interactions. Traditionally, research strategies have been based on contrasting introgressions of chromosome segments that produce male sterility with those that allow fertility. Few studies have investigated the phenotypes associated with the boundary between fertility and sterility. In this study, we cointrogressed three different X chromosome segments from Drosophila mauritiana into D. simulans. Hybrid males with these three segments are usually fertile, by conventional fertility assays. However, their spermatogenesis shows a significant slowdown, most manifest at lower temperatures. Each of the three introgressed segments retards the arrival of sperm to the seminal vesicles. Other small disturbances in spermatogenesis are evident, which altogether lead to an overall reduction in the amount of motile sperm in their seminal vesicles. These results suggest that a delay in the timing of spermatogenesis, which might be brought about by the cumulative action of many different factors of minor segment, may be the primary cause of hybrid male sterility.
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Affiliation(s)
- X R Maside
- Departamento de Bioloxía Celular e Molecular, Facultade de Ciencias, Universidade de A Coruña, 15071 A Coruña, Spain
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13
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Zhimulev IF. Polytene chromosomes, heterochromatin, and position effect variegation. ADVANCES IN GENETICS 1997; 37:1-566. [PMID: 9352629 DOI: 10.1016/s0065-2660(08)60341-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- I F Zhimulev
- Institute of Cytology and Genetics, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia
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14
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Lin TY, Viswanathan S, Wood C, Wilson PG, Wolf N, Fuller MT. Coordinate developmental control of the meiotic cell cycle and spermatid differentiation in Drosophila males. Development 1996; 122:1331-41. [PMID: 8620860 DOI: 10.1242/dev.122.4.1331] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Wild-type function of four Drosophila genes, spermatocyte arrest, cannonball, always early and meiosis I arrest, is required both for cell-cycle progression through the G2/M transition of meiosis I in males and for onset of spermatid differentiation. In males mutant for any one of these meiotic arrest genes, mature primary spermatocytes with partially condensed chromosomes accumulate and postmeiotic cells are lacking. The arrest in cell-cycle progression occurs prior to degradation of cyclin A protein. The block in spermatogenesis in these mutants is not simply a secondary consequence of meiotic cell-cycle arrest, as spermatid differentiation proceeds in males mutant for the cell cycle activating phosphatase twine. Instead, the arrest of both meiosis and spermiogenesis suggests a control point that may serve to coordinate the male meiotic cell cycle with the spermatid differentiation program. The phenotype of the Drosophila meiotic arrest mutants is strikingly similar to the histopathological features of meiosis I maturation arrest infertility in human males, suggesting that the control point may be conserved from flies to man.
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Affiliation(s)
- T Y Lin
- Department of Developmental Biology, Stanford University School of Medicine, CA 94305, USA
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15
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Hackstein JH, Hochstenbach R. The elusive fertility genes of Drosophila: the ultimate haven for selfish genetic elements. Trends Genet 1995; 11:195-200. [PMID: 7785079 DOI: 10.1016/s0168-9525(00)89043-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The Y chromosomes of Drosophila are necessary for male fertility. They carry giant genes that have some unconventional properties besides controlling the motility of the spermatozoa. Classical genetic and molecular studies suggest that evolution has favoured the close association between these genes and repetitive DNA sequences with 'selfish' traits.
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Affiliation(s)
- J H Hackstein
- Department of Microbiology and Evolutionary Biology, Faculty of Science, Catholic University of Nijmegen, Toernooiveld, The Netherlands
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16
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Mutations in supernova, indicate that this gene is required for the division of germ line cells in Drosophila. Dev Genes Evol 1995; 204:250-258. [PMID: 28306120 DOI: 10.1007/bf00208492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/1994] [Accepted: 08/24/1994] [Indexed: 10/26/2022]
Abstract
Mutations in supernova, previously shown to uncouple chromosome replication from segregation during cleavage in Drosophila embryos, also sanctions extra divisions of cystoblasts and spermatoblasts. This leads either to the formation of egg chambers which contain more than fifteen nurse cells or testes which have an excess of spermatocytes. In maturing egg chambers two potential oocytes may be specified in which case they are often ectopically located and connected with surrounding nurse cells by four ring canals. However, a typical oocyte nucleus is not always present and these chambers usually become necrotic and degenerate. The nurse cells are of variable size, but are still interconnected by a system of ring canals. They all possess a polyploid nucleus. Sequestering of maternal mRNA's from the nurse cells into the potential oocyte(s) takes place but there is no localization of this maternal information within the oocyte probably because of defective microtubule assembly. Many spermatocytes fail to complete meiosis so that bundles of spermatids are reduced in size and the males have reduced fertility. It is proposed that this gene is indirectly involved in regulating the timing of mitotic divisions in both cystoblasts and spermatoblasts through its interference with microtubule assembly which is consistent with its role during embryogenesis.
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17
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Hochstenbach R, Harhangi H, Schouren K, Hennig W. Degenerating gypsy retrotransposons in a male fertility gene on the Y chromosome of Drosophila hydei. J Mol Evol 1994; 39:452-65. [PMID: 7807535 DOI: 10.1007/bf00173414] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
During the evolution of the Y chromosome of Drosophila hydei, retrotransposons became incorporated into the lampbrush loop pairs formed by several of the male fertility genes on this chromosome. Although insertions of retrotransposons are involved in many spontaneous mutations, they do not affect the functions of these genes. We have sequenced gypsy elements that are expressed as constituents of male fertility gene Q in the lampbrush loop pair Nooses. We find that these gypsy elements are all truncated and specifically lost those sequences that may interfere with the continuity of lampbrush loop transcription. Only defective coding regions are found within the loop. Gypsy is not transcribed in loops of many other Drosophila species harboring the family. These results suggest that any contribution of gypsy to the function of male fertility gene Q does not depend on a conserved DNA sequence.
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Affiliation(s)
- R Hochstenbach
- Department of Molecular and Developmental Genetics, Faculty of Sciences, Catholic University of Nijmegen, The Netherlands
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18
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Hochstenbach R, Knops M, Hennig W. Discrimination of related transcribed and non-transcribed repetitive DNA sequences from the Y chromosomes of Drosophila hydei and Drosophila eohydei. MOLECULAR & GENERAL GENETICS : MGG 1994; 243:54-62. [PMID: 8190071 DOI: 10.1007/bf00283876] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The short arm of the Y chromosome of Drosophila hydei carries a single male fertility gene, gene Q, which forms the lampbrush loop pair Nooses. Conflicting observations have been reported concerning the identity of the repetitive DNA sequences that are transcribed in this loop pair. It has been claimed by other investigators that the loop transcripts contain repeats of two distinct, but related families of Y-specific repetitive DNA sequences, ay1 and YsI. We reinvestigated this issue, using as probes single ay1 and YsI repeats which, under stringent conditions, hybridize only to members of their own family. Under non-stringent conditions, both repeats hybridize in situ to Nooses transcripts. However, if hybridization conditions are stringent, only the ay1 probe hybridizes to loop transcripts. Hybridizations to Northern blots of testis RNA confirm these results. Further, YsI repeats are not found the closely related species D. eohydei. We conclude that the YsI repeats are not relevant for the function of fertility gene Q.
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Affiliation(s)
- R Hochstenbach
- Department of Molecular and Developmental Genetics, Faculty of Sciences, Catholic University of Nijmegen, The Netherlands
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19
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Russell SR, Kaiser K. A Drosophila melanogaster chromosome 2L repeat is expressed in the male germ line. Chromosoma 1994; 103:63-72. [PMID: 8013257 DOI: 10.1007/bf00364727] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We describe the initial characterisation of a Drosophila melanogaster locus, Mst40 (Male-specific transcript), that was cloned on the basis of its male-specific transcription during the third larval instar. Corresponding low molecular weight poly(A)+ mRNAs are abundant in primary spermatocytes, but in no other larval or adult tissue. During early embryogenesis Mst40 expression is complex; initially transcription is detected during early cleavage stages. This early expression appears as two discrete dots of hybridisation associated with each nucleus. Subsequently, the transcripts are abundant in the cytoplasm of the newly formed pole cells. In the genome Mst40 sequences are located in region 40, at the base of chromosome 2L, close to, or within, the beta-heterochromatin. The Mst40 sequences are organised as a tandemly arrayed 1.4 kb repeat unit. The repeat is conserved in all D. melanogaster strains examined but absent from other Drosophila species studied. The locus does not correspond to any known complementation groups in the region and has yet to be assigned a function.
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Affiliation(s)
- S R Russell
- Department of Genetics, University of Cambridge, UK
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Hochstenbach R, Pötgens A, Meijer H, Dijkhof R, Knops M, Schouren K, Hennig W. Partial reconstruction of the lampbrush loop pair Nooses on the Y chromosome of Drosophila hydei. Chromosoma 1993; 102:526-45. [PMID: 8243165 DOI: 10.1007/bf00368346] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We present the analysis of genomic DNA fragments that were isolated as potential segments of the lampbrush loop pair Nooses on the short arm of the Y chromosome of Drosophila hydei. More than 300 kb of DNA were recovered in BamHI lambda and cosmid clone groups. This DNA is composed of the Y-specific ay1 family of repetitive DNA sequences, and of other repetitive DNA sequences, which at least in part are also located elsewhere in the genome (Y-associated sequences). Two additional classes of DNA fragments were obtained from an EcoRI library. One of them consists of ay1 repeats without apparent interspersion, including a total of more than 300 kb of DNA. The other is composed of tandemly repeated YsI sequences, a Y-specific sequence derived from ay1. This class includes more than 400 kb of DNA, which is also not interspersed by other sequences. Our results show that only the ay1 repeats interspersed by Y-associated DNA sequences can represent parts of the 260 kb transcription unit forming the lampbrush loop, whereas the ay1 and YsI repeats without interspersion form separate and nontranscribed clusters of repetitive DNA.
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Affiliation(s)
- R Hochstenbach
- Department of Molecular and Developmental Genetics, Faculty of Sciences, Catholic University of Nijmegen, The Netherlands
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Effect of otu mutations on male fertility and spermatogenesis in Drosophila melanogaster. Dev Genes Evol 1993; 202:306-311. [DOI: 10.1007/bf00363219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/1992] [Accepted: 12/15/1992] [Indexed: 10/26/2022]
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Hackstein JH, Glätzer KH, Hulsebos TJ. Genetic and cytogenetic analysis of the "Th-Ps" region of the Y chromosome of Drosophila hydei: evidence for dual functions of the lampbrush loop-forming fertility genes? MOLECULAR & GENERAL GENETICS : MGG 1991; 227:293-305. [PMID: 2062310 DOI: 10.1007/bf00259683] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Two competing hypotheses have been proposed for the function of the Y chromosomal fertility factors in Drosophila, which form giant lampbrush loops during the primary spermatocyte stage. The first hypothesis suggests a conventional coding function, the second proposes an unconventional gene function mediated through protein binding by nascent transcripts. Therefore, we studied the genetics and cytogenetics of the two Y chromosomal fertility genes A and C of Drosophila hydei (which form the lampbrush loops threads and pseudonucleolus) in order to test the validity of these different hypotheses. Both lampbrush loops bind specific proteins, which are recognized by different antisera. Absence of either of the lampbrush loops does not interfere with the synthesis of the antigens but completely prevents the binding of the particular antigen to other lampbrush loops. Absence of the loops also does not interfere with the postmeiotic presence and localization of the particular antigen. Deletion (or inactivation) of either of the lampbrush loops threads or pseudonucleolus causes sterility of the male flies as do other male-sterile alleles of both fertility genes, which do not affect the morphology of the lampbrush loops. The phenotypic effects of these mutations on sperm morphogenesis are identical for all various male-sterile alleles of each of the fertility genes A and C, regardless of whether a particular allele leaves the loop intact, modifies that loop, or deletes (or inactivates) the loop completely. Finally, the isolation of fertile Y chromosomal mutations which modify the morphology of the lampbrush loops demonstrates that it is possible to uncouple loop morphology and genetic function. These findings do not support the hypothesis that the binding of proteins to a lampbrush loop has a substantial impact on spermiogenesis.
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Affiliation(s)
- J H Hackstein
- Department of Molecular and Developmental Genetics, Catholic University of Nijmegen, Faculty of Science, The Netherlands
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Affiliation(s)
- M Gatti
- Dipartimento di Genetica e Biologia Molecolare, Università di Roma, La Sapienza, Italy
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Bonaccorsi S, Gatti M, Pisano C, Lohe A. Transcription of a satellite DNA on two Y chromosome loops of Drosophila melanogaster. Chromosoma 1990; 99:260-6. [PMID: 2119983 DOI: 10.1007/bf01731701] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Primary spermatocyte nuclei of Drosophila melanogaster exhibit three giant lampbrush-like loops formed by the kl-5, kl-3 and ks-1 Y chromosome fertility factors. Detailed mapping of satellite DNA sequences along the Y chromosome has recently shown that AA-GAC satellite repeats are a significant component of the kl-5 and ks-1 loop-forming regions. To determine whether these simple repeated sequences are transcribed on the loop structures we performed a series of DNA-RNA in situ hybridization experiments to fixed loop preparations using as a probe cloned AAGAC repeats. These experiments showed that the probe hybridizes with homologous transcripts specifically associated with the kl-5 and ks-1 loops. These transcripts are detected at all stages of development of these two loops, do not appear to migrate to the cytoplasm and are degraded when loops disintegrate during the first meiotic prophase. Moreover, an examination of the testes revealed that the transcription of the AAGAC sequences is restricted to the loops of primary spermatocytes; the other cell types of D. melanogaster spermatogenesis do not exhibit nuclear or cytoplasmic labeling. These experiments were confirmed by RNA blotting analysis which showed that transcription of the AAGAC sequences occurs in wild-type testes but not in X/O testes. The patterns of hybridization to the RNA blots indicated that the transcripts are highly heterogeneous in size, from large (migration at limiting mobility) to less than 1 kb. We discuss the possible function of the AAGAC satellite transcripts, in the light of the available information on the Y chromosome loops of D. melanogaster.
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Affiliation(s)
- S Bonaccorsi
- Centro di Genetica Evoluzionistica del CNR, Roma, Italy
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Spermatogenesis inDrosophila hydei: A genetic survey. ACTA ACUST UNITED AC 1990; 199:251-280. [DOI: 10.1007/bf01709505] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/1990] [Accepted: 08/24/1990] [Indexed: 10/25/2022]
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Staiger CJ, Cande WZ. Microtubule distribution in dv, a maize meiotic mutant defective in the prophase to metaphase transition. Dev Biol 1990; 138:231-42. [PMID: 2407578 DOI: 10.1016/0012-1606(90)90193-m] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Microsporogenesis in Zea mays, the meiotic reduction of diploid sporocytes to haploid microspores, proceeds through a well-defined developmental sequence. The ability to generate mutants that affect the process makes this an ideal system for elucidating the role of the cytoskeleton during plant development. We have used immunofluorescence microscopy to compare microtubule distribution in wild-type and mutant microsporocytes. During normal meiosis the distribution of microtubules follows a specific temporal and spatial pattern that reflects the polar nature of microspore formation. Perinuclear microtubule staining increases and the nucleus elongates in the future spindle axis during late prophase I. Metaphase I spindles with highly focused poles align along the long axis of the anther locule. Cytokinesis occurs perpendicular to the spindle axis. The second division axis shifts 90 degrees with respect to the first division plane, thereby yielding an isobilateral tetrad of microspores. Microtubule distribution patterns during meiosis suggest that a nuclear envelope-associated microtubule organizing center (MTOC) controls the organization of cytoplasmic microtubules and contributes to spindle formation. The meiotic mutant dv is defective in the transition from a prophase microtubule array to a metaphase spindle. Instead of converging to form focused poles, the metaphase spindle poles remain diffuse as in prometaphase. This defect correlates with several abnormalities in subsequent developmental events including the formation of multinucleate daughter cells, multiple microspindles during meiosis II, multiple phragmoplasts, polyads of microspores, and cytoplasmic microtubule foci. These results suggest that dv is a mutation that affects MTOC organization.
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Affiliation(s)
- C J Staiger
- Department of Molecular and Cell Biology, University of California, Berkeley 94720
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Michiels F, Gasch A, Kaltschmidt B, Renkawitz-Pohl R. A 14 bp promoter element directs the testis specificity of the Drosophila beta 2 tubulin gene. EMBO J 1989; 8:1559-65. [PMID: 2504583 PMCID: PMC400987 DOI: 10.1002/j.1460-2075.1989.tb03540.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
To analyze the regulation of gene expression during male germ cell development, we investigated the testis-specific expression of the Drosophila beta 2 tubulin gene. Germ line transformation experiments with the upstream region of the D.melanogaster beta 2 tubulin gene fused to the Escherichia coli lacZ gene resulted in the correct tissue specific expression of the reporter gene. Furthermore, we showed that the upstream sequences of the beta 2 tubulin gene of the distantly related species D.hydei can drive the expression of the lacZ gene testis specifically in D.melanogaster flies. A detailed deletion analysis showed that 53 bp of upstream and 23 bp (D.melanogaster) or 29 bp (D.hydei) of leader sequences are sufficient to confer tissue specificity. The short promoter regions contain a 14 bp motif at identical positions in both species, which acts as a position-dependent promoter element. In vitro mutagenesis and subsequent germline transformation experiments revealed that this sequence is the only element necessary for the testis-specific transcription of the beta 2 tubulin gene in Drosophila.
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Affiliation(s)
- F Michiels
- Gentechnologische Arbeitsgruppen am MPI für Biochemie, Martinsried, FRG
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