Advertisement
JOURNAL ARTICLES
Genetic dissection of sperm individualization in Drosophila melanogaster
J.J. Fabrizio, G. Hime, S.K. Lemmon, C. Bazinet
Development 1998 125: 1833-1843;

Summary

The morphogenesis of spermatids generally takes place within a syncytium, in which all spermatid nuclei descended from a primary spermatocyte remain connected via an extensive network of cytoplasmic bridges. A late step in sperm maturation therefore requires the physical resolution of the syncytium, or cyst, into individual cells, a process sometimes referred to as sperm individualization. Despite the identification of specialized machinery involved in the individualization of Drosophila spermatids (Tokuyasu, K. T., Peacock, W. J. and Hardy, R. W. (1972) Z. Zellforsch 124, 479–506), and of many Drosophila genes mutable to male-sterile phenotypes, little is known of the mechanisms by which this extensive remodeling of the cyst is accomplished. Here, the identification of a major cytoskeletal component of the individualization complex as actin is confirmed with a simple fluorescence assay. Using rhodamine-phalloidin as a probe, the individualization complex is readily visualized forming around bundles of spermatid nuclei at one end of highly elongated cysts, then translocating along the length of the cysts. The structure of the individualization complex in a male-sterile clathrin heavy chain (Chc) mutant is observed to be reduced or disrupted relative to wild-type, consistent with the individualization-deficient phenotype of this mutant. Using the fluorescence assay, a sampling of male-sterile mutant phenotypes in which spermatogenesis proceeds to the assembly of highly elongated cysts distinguishes at least four different phenotypic classes: (1) mutations (nanking class) that block or significantly retard the assembly of the actin-based individualization complex around the nuclear bundle, (2) mutations (dud class) in which the individualization complex assembles in/around the nuclear bundle, but fails to translocate down the cyst, (3) mutations (mulet class) that allow the assembly of a morphologically normal individualization complex around the nuclear bundle, but result in a breakdown in the complex after it begins to translocate down the cyst, and (4) mutations (purity of essence class) that allow the assembly of a motile but morphologically altered or reduced individualization complex. Individualization also fails in a number of mutants with altered nuclear shape, consistent with the hypothesis that spermatid nuclei provide a physical scaffolding for the assembly of the individualization complex. Genetic analysis suggests that a substantial number of additional loci with phenotypes distinguishable with this assay remain to be identified. The large proportion of male-sterile mutations resulting in a late block to spermatogenesis, in which highly elongated cysts fail to be individualized, suggest a substantial susceptibility of this process to a broad range of cellular perturbations. The massive reorganization of cyst cytoplasm required at individualization is expected to be a correspondingly complex function requiring exquisite coordination of multiple cytoplasmic functions, and may account for the previously noted high frequency with which Drosophila genes are mutable to male-sterile phenotypes.

REFERENCES

    1. Bazinet C.,
    2. Katzen A. L.,
    3. Morgan M.,
    4. Mahowald A. P.,
    5. Lemmon S. K.
    (1993) The Drosophila clathrin heavy chain gene: Clathrin function is essential in a multicellular organism. Genetics 134, 1119–1134
    OpenUrlAbstract/FREE Full Text
    1. Bier E.,
    2. Vaessin H.,
    3. Shepard S.,
    4. Lee K.,
    5. McCall K.,
    6. Barbel S. L.,
    7. Carretto R.,
    8. Uemura T.,
    9. Grell E.,
    10. Jan L.Y.,
    11. Jan Y. N.
    (1989) Searching for pattern and mutation in the Drosophila genome with a P- lacZ vector. Genes Dev 3, 1273–1287
    OpenUrlAbstract/FREE Full Text
    1. Cant K.,
    2. Knowles B.,
    3. Mooseker M.,
    4. Cooley L.
    (1994) Drosophila singed, a fascin homolog, is required for actin bundle formation during oogenesis and bristle extension. J. Cell Biol 125, 369–380
    OpenUrlAbstract/FREE Full Text
    1. Castrillon D. H.,
    2. Gonczy P.,
    3. Alexander S.,
    4. Rawson R.,
    5. Eberhart C. G.,
    6. Viswanathan S.,
    7. DiNardo S.,
    8. Wasserman S. A.
    (1993) Toward a molecular genetic analysis of spermatogenesis in Drosophila melanogaster: Characterization of male-sterile mutants generated by single P element mutagenesis. Genetics 135, 489–505
    OpenUrlAbstract/FREE Full Text
    1. Cooley L.,
    2. Verheyen E.,
    3. Ayers K.
    (1992) chickadee encodes a profilin required for intercellular cytoplasm transport during Drosophila oogenesis. Cell 69, 173–184
    OpenUrlCrossRefPubMedWeb of Science
    1. Cooley L.,
    2. Theurkauf W.
    (1994) Cytoskeletal functions during Drosophila oogenesis. Science 266, 590–596
    OpenUrlAbstract/FREE Full Text
    1. Feinberg A. P.,
    2. Vogelstein B.
    (1983) A technique for radiolabeling DNA restriction fragments to high specific activity. Anal. Biochem 132, 6–13
    OpenUrlCrossRefPubMedWeb of Science
    1. Hackstein J. H.
    (1991) Spermatogenesis in Drosophila. A genetic approach to cellular and subcellular differentiation. Eur. J. Cell Biol 56, 151–169
    OpenUrlPubMed
    1. Kierszenbaum A.
    (1994) Mammalian spermatogenesis in vivo and in vitro: a partnership of spermatogenic and somatic cell lineages. Endocrin. Rev 15, 116–134
    OpenUrlCrossRefPubMedWeb of Science
    1. Lenz-Bohme B.,
    2. Wismar J.,
    3. Fuchs S.,
    4. Reifegerste R.,
    5. Buchner E.,
    6. Betz H.,
    7. Schmitt B.
    (1997) Insertional mutation of the Drosophila nuclear lamin Dmogene results in defective nuclear envelopes, clustering of nuclear pore complexes, and accumulation of annulate lamellae. J. Cell Biol 137, 1001–1016
    OpenUrlAbstract/FREE Full Text
    1. Lopes M. A.,
    2. Larkins B. A.
    (1993) Endosperm origin, development, and function. Plant Cell 5, 1383–1399
    OpenUrlFREE Full Text
    1. Mahajan-Milkos S.,
    2. Cooley L.
    (1994) Intercellular cytoplasm transport during Drosophila oogenesis. Dev. Biol 165, 336–351
    OpenUrlCrossRefPubMedWeb of Science
    1. Mahajan-Milkos S.,
    2. Cooley L.
    (1994) The villin-like protein encoded by the Drosophila quail gene is required for actin bundle assembly during oogenesis. Cell 78, 291–301
    OpenUrlCrossRefPubMedWeb of Science
    1. Miedema K.,
    2. Hanske M.,
    3. Akhmanova A.,
    4. Bindels P.,
    5. Hennig W.
    (1995) Minor-myosin, a novel myosin isoform synthesized preferentially in Drosophila testis is encoded by the muscle myosin heavy chain gene. Mech. Dev 51, 67–81
    OpenUrlCrossRefPubMed
    1. Postner M.,
    2. Wieschaus E.
    (1994) The nullo protein is a component of the actin-myosin network that mediates cellularization in Drosophila melanogaster embryos. J. Cell Sci 107, 1863–1873
    OpenUrlAbstract/FREE Full Text
    1. Schejter E.,
    2. Wieschaus E.
    (1993) Functional elements of the cytoskeleton in the early Drosophila embryo. Ann. Rev. Cell Biol 9, 67–99
    OpenUrlCrossRef
    1. Schejter E.,
    2. Wieschaus E.
    (1993) bottleneck acts as a regulator of the microfilament network governing cellularization of the Drosophila embryo. Cell 75, 373–385
    OpenUrlCrossRefPubMedWeb of Science
    1. Temin R. G.,
    2. Ganetzky B.,
    3. Powers P. A.,
    4. Lyttle T. W.,
    5. Pimpinelli S.,
    6. Dimitri P.,
    7. Wu C.,
    8. Hiraizumi Y.
    (1991) Segregation distorter in Drosophila melanogaster: genetic and molecular analysis. Am. Nat 137, 287–331
    OpenUrl
    1. Theriot J. A.
    (1995) The cell biology of infection by intracellular parasites. Annu. Rev. Cell Dev. Biol 11, 213–239
    OpenUrlCrossRefPubMedWeb of Science
    1. Tokuyasu K. T.,
    2. Peacock W. J.,
    3. Hardy R. W.
    (1972). Dynamics of spermiogenesis in Drosophila melanogaster. I. Individualization process. Z. Zellforsch 124, 479–506
    OpenUrlCrossRefPubMedWeb of Science
    1. Tokuyasu K. T.,
    2. Peacock W. J.,
    3. Hardy R. W.
    (1977). Dynamics of spermiogenesis in Drosophila melanogaster. VII Effects of Segregation Distorter (SD) chromosome. J. Ultrastr. Res 58, 96–107
    OpenUrlCrossRefPubMedWeb of Science
    1. Verheyen E. M.,
    2. Cooley L.
    (1994) Profilin mutations disrupt multiple actin-dependent processes during Drosophila development. Development 120, 717–728
    OpenUrlAbstract
Back to top

 Download PDF

Email
JOURNAL ARTICLES
Genetic dissection of sperm individualization in Drosophila melanogaster
J.J. Fabrizio, G. Hime, S.K. Lemmon, C. Bazinet
Development 1998 125: 1833-1843;
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
Citation Tools
Alerts

Article navigation

Other journals from The Company of Biologists

Advertisement

Kathryn Virginia Anderson (1952-2020)

Developmental geneticist Kathryn Anderson passed away at home on 30 November 2020. Tamara Caspary, a former postdoc and friend, remembers Kathryn and her remarkable contribution to developmental biology.

Zooming into 2021

In a new Editorial, Editor-in-Chief James Briscoe and Executive Editor Katherine Brown reflect on the triumphs and tribulations of the last 12 months, and look towards a hopefully calmer and more predictable year.

Read & Publish participation extends worldwide

Over 60 institutions in 12 countries are now participating in our Read & Publish initiative. Here, James Briscoe explains what this means for his institution, The Francis Crick Institute. Find out more and view our full list of participating institutions.

Upcoming special issues

Imaging Development, Stem Cells and Regeneration
Submission deadline: 30 March 2021
Publication: mid-2021

The Immune System in Development and Regeneration
Guest editors: Florent Ginhoux and Paul Martin
Submission deadline: 1 September 2021
Publication: Spring 2022

Both special issues welcome Review articles as well as Research articles, and will be widely promoted online and at key global conferences.

Development presents...

Our successful webinar series continues into 2021, with early-career researchers presenting their papers and a chance to virtually network with the developmental biology community afterwards. Sign up to join our next session:

10 February
Time: 13:00 (GMT)
Chaired by: preLights