1
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Lakhotia SC. C-value paradox: Genesis in misconception that natural selection follows anthropocentric parameters of 'economy' and 'optimum'. BBA ADVANCES 2023; 4:100107. [PMID: 37868661 PMCID: PMC10587719 DOI: 10.1016/j.bbadva.2023.100107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/24/2023] Open
Abstract
C-value paradox refers to the lack of correlation between biological complexity and the intuitively expected protein-coding genomic information or DNA content. Here I discuss five questions about this paradox: i) Do biologically complex organisms carry more protein-coding genes? ii) Does variable accumulation of selfish/ junk/ parasitic DNA underlie the c-value paradox? iii) Can nucleoskeletal or nucleotypic function of DNA explain the enigma of orders of magnitude high levels of DNA in some 'lower' taxa or in taxonomically related species? iv) Can the newly understood noncoding but functional DNA explain the c-value paradox? and, v) Does natural selection uniformly apply the anthropocentric parameters for 'optimum' and 'economy'? Answers to Q.1-5 are largely negative. Biology presents numerous 'anomalous' examples where the same end function/ phenotype is attained in different organisms through astoundingly diverse ways that appear 'illogical' in our perceptions. Such evolutionary oddities exist because natural selection, unlike a designer, exploits random and stochastic events to modulate the existing system. Consequently, persistence of the new-found 'solution/s' often appear bizarre, uneconomic, and therefore, paradoxical to human logic. The unexpectedly high c-values in diverse organisms are irreversible evolutionary accidents that persisted, and the additional DNA often got repurposed over the evolutionary time scale. Therefore, the c-value paradox is a redundant issue. Future integrative biological studies should address evolutionary mechanisms and processes underlying sporadic DNA expansions/ contractions, and how the newly acquired DNA content has been repurposed in diverse groups.
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Affiliation(s)
- Subhash C. Lakhotia
- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
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2
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Chang CH, Gregory LE, Gordon KE, Meiklejohn CD, Larracuente AM. Unique structure and positive selection promote the rapid divergence of Drosophila Y chromosomes. eLife 2022; 11:e75795. [PMID: 34989337 PMCID: PMC8794474 DOI: 10.7554/elife.75795] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 12/18/2021] [Indexed: 02/06/2023] Open
Abstract
Y chromosomes across diverse species convergently evolve a gene-poor, heterochromatic organization enriched for duplicated genes, LTR retrotransposons, and satellite DNA. Sexual antagonism and a loss of recombination play major roles in the degeneration of young Y chromosomes. However, the processes shaping the evolution of mature, already degenerated Y chromosomes are less well-understood. Because Y chromosomes evolve rapidly, comparisons between closely related species are particularly useful. We generated de novo long-read assemblies complemented with cytological validation to reveal Y chromosome organization in three closely related species of the Drosophila simulans complex, which diverged only 250,000 years ago and share >98% sequence identity. We find these Y chromosomes are divergent in their organization and repetitive DNA composition and discover new Y-linked gene families whose evolution is driven by both positive selection and gene conversion. These Y chromosomes are also enriched for large deletions, suggesting that the repair of double-strand breaks on Y chromosomes may be biased toward microhomology-mediated end joining over canonical non-homologous end-joining. We propose that this repair mechanism contributes to the convergent evolution of Y chromosome organization across organisms.
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Affiliation(s)
- Ching-Ho Chang
- Department of Biology, University of RochesterRochesterUnited States
| | - Lauren E Gregory
- Department of Biology, University of RochesterRochesterUnited States
| | - Kathleen E Gordon
- School of Biological Sciences, University of Nebraska-LincolnLincolnUnited States
| | - Colin D Meiklejohn
- School of Biological Sciences, University of Nebraska-LincolnLincolnUnited States
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3
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Mahadevaraju S, Fear JM, Akeju M, Galletta BJ, Pinheiro MMLS, Avelino CC, Cabral-de-Mello DC, Conlon K, Dell'Orso S, Demere Z, Mansuria K, Mendonça CA, Palacios-Gimenez OM, Ross E, Savery M, Yu K, Smith HE, Sartorelli V, Yang H, Rusan NM, Vibranovski MD, Matunis E, Oliver B. Dynamic sex chromosome expression in Drosophila male germ cells. Nat Commun 2021; 12:892. [PMID: 33563972 PMCID: PMC7873209 DOI: 10.1038/s41467-021-20897-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 12/22/2020] [Indexed: 01/30/2023] Open
Abstract
Given their copy number differences and unique modes of inheritance, the evolved gene content and expression of sex chromosomes is unusual. In many organisms the X and Y chromosomes are inactivated in spermatocytes, possibly as a defense mechanism against insertions into unpaired chromatin. In addition to current sex chromosomes, Drosophila has a small gene-poor X-chromosome relic (4th) that re-acquired autosomal status. Here we use single cell RNA-Seq on fly larvae to demonstrate that the single X and pair of 4th chromosomes are specifically inactivated in primary spermatocytes, based on measuring all genes or a set of broadly expressed genes in testis we identified. In contrast, genes on the single Y chromosome become maximally active in primary spermatocytes. Reduced X transcript levels are due to failed activation of RNA-Polymerase-II by phosphorylation of Serine 2 and 5.
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Affiliation(s)
- Sharvani Mahadevaraju
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Justin M Fear
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Miriam Akeju
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Brian J Galletta
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Mara M L S Pinheiro
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, SP 05508-090, São Paulo, Brazil
| | - Camila C Avelino
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, SP 05508-090, São Paulo, Brazil
| | - Diogo C Cabral-de-Mello
- Instituto de Biociências/IB, Departamento de Biologia Geral e Aplicada, UNESP-Universidade Estadual Paulista, Rio Claro, São Paulo, 13506-900, Brazil
| | - Katie Conlon
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Stafania Dell'Orso
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Zelalem Demere
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Kush Mansuria
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Carolina A Mendonça
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, SP 05508-090, São Paulo, Brazil
| | - Octavio M Palacios-Gimenez
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, SP 05508-090, São Paulo, Brazil
- Department of Evolutionary Biology and Department of Organismal Biology, Systematic Biology, Evolutionary Biology Centre, Uppsala University, 75236, Uppsala, Sweden
| | - Eli Ross
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Max Savery
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kevin Yu
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Harold E Smith
- Genomics Core, National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Vittorio Sartorelli
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Haiwang Yang
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Nasser M Rusan
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Maria D Vibranovski
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, SP 05508-090, São Paulo, Brazil
| | - Erika Matunis
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Brian Oliver
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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4
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Wang SH, Elgin SCR. The impact of genetic background and cell lineage on the level and pattern of gene expression in position effect variegation. Epigenetics Chromatin 2019; 12:70. [PMID: 31722719 PMCID: PMC6852933 DOI: 10.1186/s13072-019-0314-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 10/28/2019] [Indexed: 01/17/2023] Open
Abstract
Background Chromatin-based transcriptional silencing is often described as a stochastic process, largely because of the mosaic expression observed in position effect variegation (PEV), where a euchromatic reporter gene is silenced in some cells as a consequence of juxtaposition with heterochromatin. High levels of variation in PEV phenotypes are commonly observed in reporter stocks. To ascertain whether background mutations are the major contributors to this variation, we asked how much of the variation is determined by genetic variants segregating in the population, examining both the level and pattern of expression using the fruit fly, Drosophila melanogaster, as the model. Results Using selective breeding of a fourth chromosome PEV reporter line, 39C-12, we isolated two inbred lines exhibiting contrasting degrees of variegation (A1: low expression, D1: high expression). Within each inbred population, remarkable similarity is observed in the degree of variegation: 90% of the variation between the two inbred lines in the degree of silencing can be explained by genotype. Further analyses suggest that this result reflects the combined effect of multiple independent trans-acting loci. While the initial observations are based on a PEV phenotype scored in the fly eye (hsp70-white reporter), similar degrees of silencing were observed using a beta-gal reporter scored across the whole fly. Further, the pattern of variegation becomes almost identical within each inbred line; significant pigment enrichment in the same quadrant of the eye was found for both A1 and D1 lines despite different degrees of expression. Conclusions The results indicate that background genetic variants play the major role in determining the variable degrees of PEV commonly observed in laboratory stocks. Interestingly, not only does the degree of variegation become consistent in inbred lines, the patterns of variegation also appear similar. Combining these observations with the spreading model for local heterochromatin formation, we propose an augmented stochastic model to describe PEV in which the genetic background drives the overall level of silencing, working with the cell lineage-specific regulatory environment to determine the on/off probability at the reporter locus in each cell. This model acknowledges cell type-specific events in the context of broader genetic impacts on heterochromatin formation.
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Affiliation(s)
- Sidney H Wang
- Center for Human Genetics, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA.
| | - Sarah C R Elgin
- Department of Biology, Washington University, St Louis, MO, 63130, USA.
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5
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Buchman A, Akbari OS. Site-specific transgenesis of the Drosophila melanogaster Y-chromosome using CRISPR/Cas9. INSECT MOLECULAR BIOLOGY 2019; 28:65-73. [PMID: 30079589 PMCID: PMC8459378 DOI: 10.1111/imb.12528] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite the importance of Y-chromosomes in evolution and sex determination, their heterochromatic, repeat-rich nature makes them difficult to sequence (due, in part, to ambiguities in sequence alignment and assembly) and to genetically manipulate. Therefore, they generally remain poorly understood. For example, the Drosophila melanogaster Y-chromosome, one of the most extensively studied Y-chromosomes, is widely heterochromatic and composed mainly of highly repetitive sequences, with only a handful of expressed genes scattered throughout its length. Efforts to insert transgenes on this chromosome have thus far relied on either random insertion of transposons (sometimes harbouring 'landing sites' for subsequent integrations) with limited success or on chromosomal translocations, thereby limiting the types of Y-chromosome-related questions that could be explored. Here, we describe a versatile approach to site-specifically insert transgenes on the Y-chromosome in D. melanogaster via CRISPR/Cas9-mediated homology-directed repair. We demonstrate the ability to insert, and detect expression from, fluorescently marked transgenes at two specific locations on the Y-chromosome, and we utilize these marked Y-chromosomes to detect and quantify rare chromosomal nondisjunction effects. Finally, we discuss how this Y-docking technique could be adapted to other insects to aid in the development of genetic control technologies for the management of insect disease vectors and pests.
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Affiliation(s)
- Anna Buchman
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, 92093, United States of America
| | - Omar S. Akbari
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, 92093, United States of America
- Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA 92093, United States of America
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6
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Lakhotia SC. From Heterochromatin to Long Noncoding RNAs in Drosophila: Expanding the Arena of Gene Function and Regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1008:75-118. [PMID: 28815537 DOI: 10.1007/978-981-10-5203-3_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Recent years have witnessed a remarkable interest in exploring the significance of pervasive noncoding transcripts in diverse eukaryotes. Classical cytogenetic studies using the Drosophila model system unraveled the perplexing attributes and "functions" of the "gene"-poor heterochromatin. Recent molecular studies in the fly model are likewise revealing the very diverse and significant roles played by long noncoding RNAs (lncRNAs) in development, gene regulation, chromatin organization, cell and nuclear architecture, etc. There has been a rapid increase in the number of identified lncRNAs, although a much larger number still remains unknown. The diversity of modes of actions and functions of the limited number of Drosophila lncRNAs, which have been examined, already reflects the profound roles of such RNAs in generating and sustaining the biological complexities of eukaryotes. Several of the known Drosophila lncRNAs originate as independent sense or antisense transcripts from promoter or intergenic, intronic, or 5'/3'-UTR regions, while many of them are independent genes that produce only lncRNAs or coding as well as noncoding RNAs. The different lncRNAs affect chromatin organization (local or large-scale pan-chromosomal), transcription, RNA processing/stability, or translation either directly through interaction with their target DNA sequences or indirectly by acting as intermediary molecules for specific regulatory proteins or may act as decoys/sinks, or storage sites for specific proteins or groups of proteins, or may provide a structural framework for the assembly of substructures in nucleus/cytoplasm. It is interesting that many of the "functions" alluded to heterochromatin in earlier cytogenetic studies appear to find correlates with the known subtle as well as far-reaching actions of the different small and long noncoding RNAs. Further studies exploiting the very rich and powerful genetic and molecular resources available for the Drosophila model are expected to unravel the mystery underlying the long reach of ncRNAs.
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Affiliation(s)
- Subhash C Lakhotia
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221005, India.
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7
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Lakhotia SC. Non-coding RNAs demystify constitutive heterochromatin as essential modulator of epigenotype. THE NUCLEUS 2017. [DOI: 10.1007/s13237-017-0221-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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8
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Voelker RA, Kojima KI. FERTILITY AND FITNESS OF XO MALES IN DROSOPHILA. II. QUANTITATIVE ANALYSIS. Evolution 2017; 26:560-573. [PMID: 28563346 DOI: 10.1111/j.1558-5646.1972.tb01964.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/1972] [Indexed: 11/28/2022]
Affiliation(s)
- Robert A Voelker
- Department of Zoology, University of Texas, Austin, Texas, 78712
| | - Ken-Ichi Kojima
- Department of Zoology, University of Texas, Austin, Texas, 78712
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9
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Voelker RA, Kojima KI. FERTILITY AND FITNESS OF XO MALES IN DROSOPHILA I. QUALITATIVE STUDY. Evolution 2017; 25:119-128. [PMID: 28562944 DOI: 10.1111/j.1558-5646.1971.tb01865.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/1970] [Indexed: 11/27/2022]
Affiliation(s)
- Robert A Voelker
- Department of Zoology, University of Texas, Austin, Texas, 78712
| | - Ken-Ichi Kojima
- Department of Zoology, University of Texas, Austin, Texas, 78712
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10
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Abstract
Drosophila melanogaster spermatids undergo dramatic morphological changes as they differentiate from small round cells approximately 12 μm in diameter into highly polarized, 1.8 mm long, motile sperm capable of participating in fertilization. During spermiogenesis, syncytial cysts of 64 haploid spermatids undergo synchronous differentiation. Numerous changes occur at a subcellular level, including remodeling of existing organelles (mitochondria, nuclei), formation of new organelles (flagellar axonemes, acrosomes), polarization of elongating cysts and plasma membrane addition. At the end of spermatid morphogenesis, organelles, mitochondrial DNA and cytoplasmic components not needed in mature sperm are stripped away in a caspase-dependent process called individualization that results in formation of individual sperm. Here, we review the stages of Drosophila spermiogenesis and examine our current understanding of the cellular and molecular mechanisms involved in shaping male germ cell-specific organelles and forming mature, fertile sperm.
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Affiliation(s)
- Lacramioara Fabian
- Cell Biology Program; The Hospital for Sick Children (SickKids); Toronto, ON Canada
| | - Julie A. Brill
- Cell Biology Program; The Hospital for Sick Children (SickKids); Toronto, ON Canada
- Department of Molecular Genetics; University of Toronto; Toronto, ON Canada
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11
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Hareven D, Zuckerman M, Lifschytz E. Origin and evolution of the transcribed repeated sequences of the Y chromosome lampbrush loops of Drosophila hydei. Proc Natl Acad Sci U S A 2010; 83:125-9. [PMID: 16593641 PMCID: PMC322804 DOI: 10.1073/pnas.83.1.125] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The molecular evolution and patterns of conservation of clones from four Y chromosome lampbrush loops of Drosophila hydei were investigated. Each loop contains a discrete family of transcribed repeats that are only slightly conserved even in the hydei subgroup species. Sequencing of clones from the four D. hydei loops indicates that all transcribed repeats evolved from A+T-rich elements of the genome. Evidence is presented that suggests a Y-specific family evolved as a result of the transposition of repeated sequences from an autosomal site to the Y chromosome with the concomitant acquisition of transcriptional activity and loss of non-Y sequences. The results support a structural role for the loops in shaping a spermatocyte-specific nuclear organization. Transcribed heterochomatic sequences could play a similar role in nuclear organization in many cell types.
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Affiliation(s)
- D Hareven
- Department of Biology, Technion Haifa 32000, Israel
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12
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Friedländer M, Scholtz CH. Two different patterns of interrupted spermatogenesis in winter diapause and summer quiescence in the desert beetle,Omorgus freyi. J Morphol 2005; 218:347-358. [DOI: 10.1002/jmor.1052180309] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Abstract
The Drosophila melanogaster Y chromosome has long been known to contain few functional genes other than several required for male fertility. The D. melanogaster genome sequence has now allowed characterization of two more male fertility genes, shedding light on the function and evolution of Y chromosomes.
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Affiliation(s)
- B Charlesworth
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh EH9 3JT, UK.
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14
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Reugels AM, Kurek R, Lammermann U, Bünemann H. Mega-introns in the dynein gene DhDhc7(Y) on the heterochromatic Y chromosome give rise to the giant threads loops in primary spermatocytes of Drosophila hydei. Genetics 2000; 154:759-69. [PMID: 10655227 PMCID: PMC1460963 DOI: 10.1093/genetics/154.2.759] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The heterochromatic Y chromosomes of several Drosophila species harbor a small number of male fertility genes (fertility factors) with several unusual features. Expression of their megabase-sized loci is restricted to primary spermatocytes and correlates with the unfolding of species-specific lampbrush loop-like structures resulting from huge transcripts mainly derived from clusters of loop-specific Y chromosomal satellites. Otherwise, there is evidence from genetic mapping and biochemical experiments that at least two of these loops, Threads in Drosophila hydei and kl-5 in D. melanogaster, colocalize with the genes for the axonemal dynein beta heavy chain proteins DhDhc7(Y) and Dhc-Yh3, respectively. Here, we make use of particular Threads mutants with megabase-sized deletions for direct mapping of DhDhc7(Y)-specific exons among the large clusters of satellite DNA within the 5.1-Mb Threads transcription unit. PCR experiments with exon-specific primer pairs, in combination with hybridization experiments with exon- and satellite-specific probes on filters with large PFGE-generated DNA fragments, offer a simple solution for the long-lasting paradox between megabase-sized loops and protein-encoding transcription units; the lampbrush loops Threads and the DhDhc7(Y) gene are one and the same transcription unit, and the giant size of the DhDhc7(Y) gene as well as its appearance as a giant lampbrush loop are merely the result of transcription of huge clusters of satellite DNA within some of its 20 introns.
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Affiliation(s)
- A M Reugels
- Institut für Genetik, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany
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15
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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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16
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Schmidt A, Palumbo G, Bozzetti MP, Tritto P, Pimpinelli S, Schäfer U. Genetic and molecular characterization of sting, a gene involved in crystal formation and meiotic drive in the male germ line of Drosophila melanogaster. Genetics 1999; 151:749-60. [PMID: 9927466 PMCID: PMC1460476 DOI: 10.1093/genetics/151.2.749] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The sting mutation, caused by a P element inserted into polytene region 32D, was isolated by a screen for male sterile insertions in Drosophila melanogaster. This sterility is correlated with the presence of crystals in spermatocytes and spermatids that are structurally indistinguishable from those produced in males carrying a deficiency of the Y-linked crystal (cry) locus. In addition, their morphology is needle-like in Ste+ flies and star-shaped in Ste flies, once again as observed in cry- males. The sti mutation leads to meiotic drive of the sex chromosomes, and the strength of the phenomenon is correlated with the copy number of the repetitive Ste locus. The same correlation is also true for the penetrance of the male sterile mutation. A presumptive sti null allele results in male sterility and lethal maternal effect. The gene was cloned and shown to code for a putative protein that is 866 amino acids long. A C-terminal domain of 82 amino acids is identified that is well conserved in proteins from different organisms. The gene is expressed only in the germline of both sexes. The interaction of sting with the Ste locus can also be demonstrated at the molecular level. While an unprocessed 8-kb Ste primary transcript is expressed in wild-type males, in X/Y homozygous sti males, as in X/Y cry- males, a 0.7-kb mRNA is produced.
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Affiliation(s)
- A Schmidt
- Institut für Genetik, Heinrich-Heine-Universität, D-40225 D usseldorf, Germany
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17
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Bhasin S, Ma K, Sinha I, Limbo M, Taylor WE, Salehian B. The genetic basis of male infertility. Endocrinol Metab Clin North Am 1998; 27:783-805, viii. [PMID: 9922908 DOI: 10.1016/s0889-8529(05)70041-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Defective spermatogenesis can be the end result of a multitude of causes, such as systemic disease, malnutrition, endocrinologic disorder, genetic defects, anatomic obstruction of the passage of spermatozoa, infections, and environmental toxins. A genetic basis of infertility is thought to exist in a majority of infertile men currently classified as having idiopathic infertility. Despite advances in molecular technology, the pathophysiology of spermatogenic failure in a majority of infertile men remains unknown. Although a large number of genes and loci in experimental animals are associated with sterility, the human homologues of most of these genes have not been cloned yet. Infertility is a heterogeneous syndrome in men; therefore, it is likely that a multitude of genes and loci will be implicated in different infertility subsets.
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Affiliation(s)
- S Bhasin
- Division of Endocrinology, Metabolism and Molecular Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California, USA
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18
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Kurek R, Reugels AM, Glätzer KH, Bünemann H. The Y chromosomal fertility factor Threads in Drosophila hydei harbors a functional gene encoding an axonemal dynein beta heavy chain protein. Genetics 1998; 149:1363-76. [PMID: 9649526 PMCID: PMC1460245 DOI: 10.1093/genetics/149.3.1363] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To understand the contradiction between megabase-sized lampbrush loops and putative protein encoding genes both associated with the loci of Y chromosomal fertility genes of Drosophila on the molecular level, we used PCR-mediated cloning to identify and isolate the cDNA sequence of the Y chromosomal Drosophila hydei gene DhDhc7(Y). Alignment of the sequences of the putative protein DhDhc7(Y) and the outer arm dynein beta heavy chain protein DYH2 of Tripneustes gratilla shows homology over the entire length of the protein chains. Therefore the proteins can be assumed to fulfill orthologous functions within the sperm tail axonemes of both species. Functional dynein beta heavy chain molecules, however, are necessary for the assembly and attachment of outer dynein arms within the sperm tail axoneme. Localization of DhDhc7(Y) to the fertility factor Threads, comprising at least 5.1 Mb of transcriptionally active repetitive DNA, results from an infertile Threads- mutant where large clusters of Threads specifically transcribed satellites and parts of DhDhc7(Y) encoding sequences are missing simultaneously. Consequently, the complete lack of the outer dynein arms in Threads- males most probably causes sperm immotility and hence infertility of the fly. Moreover, preliminary sequence analysis and several other features support the hypothesis that DhDhc7(Y) on the lampbrush loops Threads in D. hydei and Dhc-Yh3 on the lampbrush loops kl-5 in Drosophila melanogaster on the heterochromatic Y chromosome of both species might indeed code for orthologous dynein beta heavy chain proteins.
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Affiliation(s)
- R Kurek
- Dipartimento di Genetica e Biologia Molecolare, Universita di Roma 'La Sapienza,' I-00185 Roma, Italia
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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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20
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Kurek R, Trapitz P, Bünemann H. Strukturdifferenzierungen in Y-chromosom von Drosophila hydei: the unique morphology of the Y chromosomal lampbrush loops Threads results from 'coaxial shells' formed by different satellite-specific subregions within megabase-sized transcripts. Chromosome Res 1996; 4:87-102. [PMID: 8785614 DOI: 10.1007/bf02259701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The results of pulsed-field gel electrophoresis (PFGE) analysis and two-colour transcript fluorescence in situ hybridization (FISH) for the three Threads-specific DNA satellites YLII, YLI and rally are in support of long-range clustering of these sequence families within the subterminal region on the long arm of the Y chromosome of Drosophila hydei. On the basis of the linear arrangement of at least four extended clusters of satellite-specific sequences, the loop morphology of wild-type and several mutant Threads can be explained by assumption of a single Threads-specific transcription unit comprising about 5.1 Mb of repetitive DNA located between the Pseudonucleolus and the Nucleolus organizer. Transcription is unidirectional from the Pseudonucleolus towards the terminally located Nucleolus organizer. Transcripts most likely start in front of or within the 3.2 Mb region of YLII-related sequences, pass through subsequent blocks of 1.2 and 0.3 Mb of YLI- and rally-related sequences, respectively, and cease within the region of a smaller block of YLI-related repeats. The megabase-sized transcripts remain physically linked to the DNA axis and their extended satellite-specific regions form coaxial clouds or shells around the central DNA axis. In this way each cluster of earlier-transcribed sequences generates a cloud or shell on top of the later-transcribed ones. According to this model of 'satellite-specific coaxial shells' the tube-like morphology and other peculiarities of the Y chromosomal lampbrush loops Threads can be explained as a result of satellite-specific RNA superstructures and/or formation of extended ribonucleoprotein (RNP) complexes between clusters of satellite-specific transcripts and specific proteins. On the basis of this model the specific morphology of several Threads mutants can be interpreted as the result of large interstitial or terminal deletions that alter the total length of the Threads-specific transcription unit without exerting other major effects on principal features of the transcription process along the Threads.
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Affiliation(s)
- R Kurek
- Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Germany
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21
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Quagio-Grassiotto I, De Lello E. Cytoplasmic bridges, intercellular junctions, and individualization of germ cells during spermatogenesis in Dermatobia hominis (Diptera: Cuterebridae). J Morphol 1996; 227:145-154. [PMID: 29852591 DOI: 10.1002/(sici)1097-4687(199602)227:2<145::aid-jmor2>3.0.co;2-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
During mitotic and meiotic divisions in Dermatobia hominis spermatogenesis, the germ cells stay interlinked by cytoplasmic bridges as a result of incomplete cytokinesis. By the end of each division, cytoplasmic bridges flow to the center of the cyst, forming a complex, called the fusoma. During meiotic prophase I, spermatocytes I present desmosome-like junctions and meiotic cytoplasmic bridges. At the beginning of spermiogenesis, the fusoma moves to the future caudal end of the cyst, and at this time the early spermatids are linked by desmosome-like junctions. Throughout spermiogenesis, new and sometimes broad cytoplasmic bridges are formed among spermatids at times making them share cytoplasm. In this case the individualization of cells is assured by the presence of smooth cisternae that outline their structures. The more differentiated spermatids have in addition to narrow cytoplasmic bridges, plasmic membranes junctions. By the end of spermiogenesis, the excess cytoplasmic mass is eliminated leading to spermatid individualization. Desmosome-like junctions of spermatocytes I and early spermatids appear during the fusoma readjustment and segregations; on the other hand, plasmic membrane junctions appear in differentiating spermatids and are eliminated along with the cytoplasmic excess. These circumstances suggest that belt desmosome-like and plasmic membrane junctions are involved in the maintenance of the relative positions of male germ cells in D. hominis while they are inside the cysts. © 1996 Wiley-Liss, Inc.
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Affiliation(s)
| | - Edy De Lello
- Department of Morphology, Institute of Biosciences, UNESP 18618-000, Botucatu, SP, Brazil
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22
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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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Hochstenbach R, Brand R, Hennig W. Transcription of repetitive DNA sequences in the lampbrush loop pair Nooses formed by sterile alleles of fertility gene Q on the Y chromosome of Drosophila hydei. MOLECULAR & GENERAL GENETICS : MGG 1994; 244:653-60. [PMID: 7969035 DOI: 10.1007/bf00282756] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The Y chromosomal lampbrush loop-forming male fertility genes of Drosophila consist mainly of repetitive DNA sequences that do not code for proteins. We investigated whether differences in the transcription of these sequences can be detected in male-sterile alleles of male fertility gene Q, which forms the loop pair Nooses. The loop consists, for approximately two-thirds, of repeats of the Y-specific ay1 family of repetitive DNA sequences. Of the remaining one-third, at least one-half is represented by defective retrotransposons of the gypsy family. Both sequence types are interspersed throughout the loop. Using both ay1 and gypsy sequences as probes for transcript in situ hybridization, we show that, at the level of the light microscope, transcription of neither sequence is detectably affected in the loops formed by a male-sterile allele of gene Q. We conclude that the transcription of ay1 and gypsy is required, but not sufficient for the function of 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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Pitnick S, Markow TA. Large-male advantages associated with costs of sperm production in Drosophila hydei, a species with giant sperm. Proc Natl Acad Sci U S A 1994; 91:9277-81. [PMID: 7937755 PMCID: PMC44795 DOI: 10.1073/pnas.91.20.9277] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Males of the fruit fly Drosophila hydei were found to produce 23.47 +/- 0.46-mm-long spermatozoa, the longest ever described. No relationship was found between male body size and sperm length. We predicted that if these giant gametes are costly for males to produce, then correlations should exist between male body size, rates of sperm production, and fitness attributes associated with the production of sperm. Smaller males were found to make a greater relative investment in testicular tissue growth, even though they have shorter and thinner testes. Smaller males were also found to (i) be maturing fewer sperm bundles within the testes at any point in time than larger males, (ii) require a longer period of time post-eclosion to become reproductively mature, (iii) mate with fewer females, (iv) transfer fewer sperm per copulation, and (v) produce fewer progeny. The significance of these findings for body size-related fitness and the question of sperm size evolution are discussed.
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Affiliation(s)
- S Pitnick
- Department of Zoology, Arizona State University, Tempe 85287-1501
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25
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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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26
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Trapitz P, Glätzer KH, Bünemann H. Towards a physical map of the fertility genes on the heterochromatic Y chromosome of Drosophila hydei: families of repetitive sequences transcribed on the lampbrush loops Nooses and Threads are organized in extended clusters of several hundred kilobases. MOLECULAR & GENERAL GENETICS : MGG 1992; 235:221-34. [PMID: 1465096 DOI: 10.1007/bf00279364] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The understanding of structure and function of the so-called fertility genes of Drosophila is very limited due to their unusual size--several megabases--and their location on the heterochromatic Y chromosome. Since mapping of these genes has mainly been done by classical cytogenetic analyses using a small number of cytologically visible lampbrush loops as the sole markers for particular fertility genes, the resolution of the genetic map of the Y chromosome is restricted to 3-5 Mb. Here we demonstrate that a substantially finer subdivision of the megabase-sized fertility genes in the subtelomeric regions of the Y chromosome of Drosophila hydei can be achieved by a combination of digestion with restriction enzymes having 6 bp recognition sequences, and pulsed field gel electrophoresis. The physical subdivision is based upon large conserved fragments of repetitive DNA in the size range from 50 up to 1600 kb and refers to the long-range organization of several families of repetitive DNA involved in Y chromosomal transcription processes in primary spermatocytes. We conclude from our results that at least five different families of repetitive DNA specifically transcribed on the lampbrush loops nooses and threads are organized as extended clusters of several hundred kb, essentially free of interspersed non-repetitive sequences.
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Affiliation(s)
- P Trapitz
- Institut für Genetik, Heinrich-Heine-Universität Düsseldorf, FRG
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27
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Higher order structure of Balbiani ring premessenger RNP particles depends on certain RNase A sensitive sites. J Mol Biol 1990; 215:93-101. [PMID: 2398499 DOI: 10.1016/s0022-2836(05)80098-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Specific premessenger ribonucleoprotein (RNP) particles, the Balbiani ring (BR) granules from Chironomus tentans salivary glands, were treated with RNase A to study the effect of RNA strand breaks on the higher order structure of the particles. Isolated, radioactively labeled BR granules, known to sediment at 300 S, were digested with RNase A and centrifuged in sucrose gradients. The fractionated particles were subsequently analyzed using electron microscopy and caesium chloride centrifugation. At a low RNase concentration, most of the 300 S particles disintegrated completely, and no metastable degradation products were observed. At intermediate RNase concentrations, no 300 S particles were left, but a minor fraction of the BR granules had unfolded and sedimented at 160 S. These granules could represent particles modified during the RNase treatment or represent a more slowly degrading subfraction of the particles. At a high RNase concentration, no RNP particles at all remained in the gradient. The rapid disintegration of the majority of the BR granules was investigated further by electrophoretic analysis of RNA in the remaining particles. During the RNase treatment BR granules, still sedimenting at 300 S, accumulated strand breaks; in fact, as many as 50 to 100 nicks in the 37 kb RNA could be tolerated. It was concluded from RNA analyses that the disintegration of the BR granules was not dependent on any single nick in the RNA, nor on the accumulation of a certain number of nicks, but rather on one or a few critical strand breaks. We propose that there are organizing sequences essential for particle integrity; once these sequences are nicked, the premessenger RNP particles are rapidly and completely degraded.
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28
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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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29
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Affiliation(s)
- W Hennig
- Department of Molecular and Developmental Genetics, Katholieke Universiteit, Nijmegen, The Netherlands
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30
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Wlaschek M, Awgulewitsch A, Bünemann H. Structure and function of Y chromosomal DNA. I. Sequence organization and localization of four families of repetitive DNA on the Y chromosome of Drosophila hydei. Chromosoma 1988; 96:145-58. [PMID: 3349874 DOI: 10.1007/bf00331047] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The sequence organization of four different families of Y chromosomal repetitive DNA is characterized at three levels of spatial extension along the Y chromosome of Drosophila hydei. At the lowest level of resolution, DNA blot analysis of Y chromosomal fragments of different lengths and in situ hybridization experiments on metaphase chromosomes demonstrate the clustering of each particular sequence family within one defined region of the chromosome. At a higher level of resolution, family specific repeats can be detected within these clusters by crosshybridization within 10-20 kb long continuous stretches of cloned DNA in EMBL3 phages. At the highest level of resolution, detailed sequence analysis of representative subclones about 1 kb in length reveals a satellite-like head to tail arrangement of family specific degenerated subrepeats as the building scheme common to all four families. Our results provide the first comparative sequence analysis of three novel families of repetitive DNA on the long arm of the Y chromosome of D. hydei. Additional data are presented which support the existence of two related subfamilies of repetitive DNA on the short arm of the Y chromosome.
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Affiliation(s)
- M Wlaschek
- Institut für Genetik der Universität, Düsseldorf, Federal Republic of Germany
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31
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Affiliation(s)
- J H Hackstein
- Department of Genetics, Katholieke Universiteit, Nijmegen, The Netherlands
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32
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Lifschytz E. The developmental program of spermiogenesis in Drosophila: a genetic analysis. INTERNATIONAL REVIEW OF CYTOLOGY 1987; 109:211-58. [PMID: 3323107 DOI: 10.1016/s0074-7696(08)61723-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- E Lifschytz
- Department of Biology, TECHNION-Israel Institute for Technology, Haifa
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35
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36
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Pimpinelli S, Bonaccorsi S, Gatti M, Sandler L. The peculiar genetic organization of Drosophila heterochromatin. Trends Genet 1986. [DOI: 10.1016/0168-9525(86)90163-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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37
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Awgulewitsch A, Bünemann H. Isolation of Y-chromosomal repetitive DNA sequences of Drosophila hydei via enrichment of chromosome-specific sequences by heterogeneous hybridization between female and male DNA. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 1986; 12:37-50. [PMID: 3944419 DOI: 10.1016/0165-022x(86)90049-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Male or female DNA of Drosophila hydei was sheared by sonication, denatured, reannealed to different C0t-values and fractionated by hydroxyapatite. The highly repetitive, moderately repetitive and unique fractions of female DNA were denatured again and coupled via diazotization or cyanogen bromide to macroporous Sephacryl S-500. Enrichment of Y-chromosomal sequences was achieved by cycling each of the different fractions of male DNA under optimized hybridization conditions over a column with a manifold excess of immobilized female DNA of the corresponding complexity. Thereby, Y-chromosomal sequences of D. hydei could be enriched about 100-fold for highly and moderately repetitive DNA and about 10-fold for unique DNA. When a library of male D. hydei DNA was screened with Y-enriched highly repetitive DNA, more than 98% of all hybridizing phages contained inserts of repetitive Y-chromosomal DNA of at least four different sequence families.
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38
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Hybrid dysgenesis-induced Y chromosomal sterility in Drosophila melanogaster. ACTA ACUST UNITED AC 1985. [DOI: 10.1007/bf00383333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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39
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Lifshytz E, Hareven D. Molecular evidence for partial inactivation of Y loops in T(X:Y)56 males from D. hydei. MOLECULAR & GENERAL GENETICS : MGG 1985; 199:46-52. [PMID: 3858632 DOI: 10.1007/bf00327507] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Using loop-specific DNA clones, we established that the T(X:Y)56 (Hackstein and Hennig 1982) chromosome, formerly thought to be deleted for the Yshort arm and the associated 'nooses' loops is actually an XYS X YL combination. It carries, adjacent to the translocation junction, the complete and uninterrupted set of the two dysfunctional 'nooses' domains. The morphologically altered and functionally defective loops are transcribed at about 50% of the normal rate. Transcripts in one of the two 'nooses' domains are preferentially underrepresented and their distribution in the spermatocyte nucleus is distorted, presumably as a consequence of a spreading effect. No alteration in transcript size or in the correct strand selection, and no variegation of transcription on the single spermatocyte level, were observed. In another translocation T(X:Y)97, in which 'tubular ribbons' were reported to be inactivated (Hess 1970), complete elimination of DNA sequences is observed. A possible mechanism for the position effect inactivation of Y loops in X:Y translocations is discussed briefly.
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40
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Hennig W. Y chromosome function and spermatogenesis in Drosophila hydei. ADVANCES IN GENETICS 1985; 23:179-234. [PMID: 3887859 DOI: 10.1016/s0065-2660(08)60513-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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41
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Hanna PJ, Gl�tzer KH, Liebrich W, Hess O. Genetic factors affecting normal growth of testes inDrosophila hydei. ACTA ACUST UNITED AC 1985. [DOI: 10.1007/bf00848313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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42
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Glätzer KH. Preservation of nuclear RNP antigens in male germ cell development of Drosophila hydei. ACTA ACUST UNITED AC 1984. [DOI: 10.1007/bf00328055] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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43
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Lifschytz E, Hareven D, Azriel A, Brodsly H. DNA clones and RNA transcripts of four lampbrush loops from the Y chromosome of Drosophila hydei. Cell 1983; 32:191-9. [PMID: 6186391 DOI: 10.1016/0092-8674(83)90509-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Drosophila hydei clones representing transcribed middle-repetitive sequences from four of six major lampbrush loops of the Y chromosome were isolated. Sequences homologous to each clone are clustered in a particular locus on the Y chromosome, but additional euchromatic sites were found for one of the transcribed clones. In situ hybridization to lampbrush-loops RNA permitted the identification of clones homologous with the two "nooses" loops on YS and with the "clubs" and "tubular ribbons" on the YL arm. Loop-specific nuclear RNA molecules range in size from 10S to 60S. Loop RNA is accumulated in the nucleus and remains attached to the loops during the course of primary spermatocyte growth. It disappears, however, along with the loop structures, during the first meiotic prophase. The structure and function of the Y chromosome and its lampbrush loops are briefly considered in the light of these findings.
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44
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Hazelrigg T, Fornili P, Kaufman TC. A cytogenetic analysis of X- ray induced male steriles on the Y chromosome of Drosophila melanogaster. Chromosoma 1982. [DOI: 10.1007/bf00333474] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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45
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Abstract
The Y chromosome of Drosophila carries fertility genes which, in part, develop lampbrush loops during the meiotic prophase. Hybrid males from crosses between D. hydei and D. neohydei are fertile although the morphology of the lampbrush loops differs between both species. With the aid of X ray induced "hybrid" X-Y translocation chromosomes the question has been studied whether Y chromosomal genes of D. neohydei can substitute deletions in the Y chromosome of D. hydei. Although the induction of translocation chromosomes almost regularly results in an inactivation of the translocated Y fragment within a few generations, one case of successful complementation has been demonstrated. Furthermore, a new lampbrush loop pair has been detected in D. neohydei which is morphologically similar to the "nooses" of D. hydei. Preliminary evidence for the location of the lampbrush loops on the Y chromosome of D. neohydei is discussed.
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46
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47
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Bull JJ. Evolution of environmental sex determination from genotypic sex determination. Heredity (Edinb) 1981. [DOI: 10.1038/hdy.1981.74] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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48
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Kloetzel PM, Knust E, Schwochau M. Analysis of nuclear proteins in primary spermatocytes of Drosophila hydei: The correlation of nuclear proteins with the function of the Y chromosomal loops. Chromosoma 1981; 84:67-86. [PMID: 7297252 DOI: 10.1007/bf00293364] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The protein content of spermatocyte nuclei from X/Y males and mutants of D. hydei which lack different Y chromosomal loop forming sites, was compared with that of X/0 males in 14C/3H double labelling experiments. Proteins of 45,000, 52,000, 54,000, 66,000, 80,000, 84,000 and 170,000 Dalton are found to be enriched in nuclei containing two or more active Y chromosomal loop forming sites. These proteins are also present in the nuclei of X0 males. In the complete absence of the Y-chromosomal loops proteins of 35,000, 46,000, 58,000 and 110,000 Dalton become enriched in the spermatocyte nuclei. - Analysis of the nuclear RNP of spermatocytes led to the isolation of an hnRNP-containing fraction with an S-value of greater than 900S (RNP-PP), - In the RNP-PP of XY males labelled protein material associated with hnRNA is enriched by a factor of approximately 3 in respect to the X0 genotype. The nuclear RNP has a heterogenous buoyant density in CsCl of rho = 1.33 to 1.43 g/cm3. RNase T1 treatment of the crude nuclear RNP from XY males prior to sucrose gradient analysis shows that the 66,000 Dalton protein which is also strongly enriched in the nuclei in the presence of active Y chromosomal loop forming sites, is the main protein associated with protected RNA-sequences of 80-120- 300 nucleotides in length. Competitive nitrocellulose filter binding assays reveal that the 66,000 Dalton protein predominantly forms in 2 M NaCl stable RNA/protein complexes with the poly A+hnRNA of the RNP-PP. Those RNP complexes have a buoyant density of rho = 1.43 g/cm3 in CsCl. The results are discussed in relation to the nuclear structure and the function of the Y chromosomal loops during spermatogenesis in Drosophila hydei.
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Hanna PJ. Inhibition of Y-chromosome loop formation in primary spermatocyte nuclei ofDrosophila hydei by trimethylphosphate. ACTA ACUST UNITED AC 1981. [DOI: 10.1007/bf01971772] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Hardy RW, Tokuyasu KT, Lindsley DL. Analysis of spermatogenesis in Drosophila melanogaster bearing deletions for Y-chromosome fertility genes. Chromosoma 1981; 83:593-617. [PMID: 6794995 DOI: 10.1007/bf00328522] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The effects of spermatogenesis of a series of continguous non-overlapping Y-chromosome deficiencies were examined using both the light and electron microscope. The deficiencies were constructed by combining elements of different X-Y translocations; they subdivide the Y into seven segments, six of which are required for male fertility (four in the long arm and two in the short arm). Spermatogenesis was examined from the primary spermatocyte through to the formation of mature sperm and the earliest departures from normal development identified. Two deficiencies result in the absence of the same structure from the axoneme of the sperm tail--the dynein-containing outer arm extending from the A subtubule of the peripheral doublet; they also result in the absence from primary spermatocyte nuclei of aggregates of tubuli in one case and reticular material in the other. A third deficiency causes the appearance in the primary spermatocyte of the crystals characteristic of X0 males and the irregular distribution during meiosis of nuclear and cytoplasmic elements to the spermatids. The fourth deficiency results in the misalignment of the developing axoneme with the mitochondrial derivatives and is first detectable in the onion nebenkern stage of the spermatid. Finally for two deficiencies the first abnormalities detected were during later stages and comprise a syndrome found in most of the steriles. We attribute this phenotype to the indirect effects of earlier lesions.
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