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Updated: Jul 8, 2026
Ex vivo Culture of Drosophila Pupal Testis and Single Male Germ-line Cysts: Dissection, Imaging, and Pharmacological Treatment
Published on: September 11, 2014
The role of Drosophila Merlin in spermatogenesis
Natalia V Dorogova1, Elena M Akhmametyeva, Sergei A Kopyl
1Institute of Cytology and Genetics, Russian Academy of Sciences, Novosibirsk, Russia. natdorogova@rambler.ru
Background:
Drosophila Merlin, the homolog of the human Neurofibromatosis 2 (NF2) gene, is important for the regulation of cell proliferation and receptor endocytosis. Male flies carrying a Mer3 allele, a missense mutation (Met177-->Ile) in the Merlin gene, are viable but sterile; however, the cause of sterility is unknown.
Results:
Testis examination reveals that hemizygous Mer3 mutant males have small seminal vesicles that contain only a few immotile sperm. By cytological and electron microscopy analyses of the Mer3, Mer4 (Gln170-->stop), and control testes at various stages of spermatogenesis, we show that Merlin mutations affect meiotic cytokinesis of spermatocytes, cyst polarization and nuclear shaping during spermatid elongation, and spermatid individualization. We also demonstrate that the lethality and sterility phenotype of the Mer4 mutant is rescued by the introduction of a wild-type Merlin gene. Immunostaining demonstrates that the Merlin protein is redistributed to the area associated with the microtubules of the central spindle in telophase and its staining is less in the region of the contractile ring during meiotic cytokinesis. At the onion stage, Merlin is concentrated in the Nebenkern of spermatids, and this mitochondrial localization is maintained throughout sperm formation. Also, Merlin exhibits punctate staining in the acrosomal region of mature sperm.
Conclusion:
Merlin mutations affect spermatogenesis at multiple stages. The Merlin protein is dynamically redistributed during meiosis of spermatocytes and is concentrated in the Nebenkern of spermatids. Our results demonstrated for the first time the mitochondrial localization of Merlin and suggest that Merlin may play a role in mitochondria formation and function during spermatogenesis.
Insights
Merlin mutations disrupt male fertility in Drosophila by affecting multiple stages of spermatogenesis, including meiotic cytokinesis and sperm development. This study reveals Merlin
Area of Science:
- Cell Biology
- Genetics
- Developmental Biology
Background:
- Drosophila Merlin is a homolog of human NF2, regulating cell proliferation and endocytosis.
- Merlin mutations in male flies cause sterility, but the underlying mechanisms are unclear.
Purpose of the Study:
- Investigate the role of Merlin in male Drosophila fertility.
- Determine the specific defects in spermatogenesis caused by Merlin mutations.
Main Methods:
- Cytological and electron microscopy of testes from Merlin mutant and control flies.
- Analysis of Merlin protein localization via immunostaining.
- Genetic rescue experiments for Merlin mutants.
Main Results:
- Merlin mutations impair meiotic cytokinesis, cyst polarization, nuclear shaping, and spermatid individualization.
- Merlin protein dynamically localizes to the central spindle during meiosis and mitochondria (Nebenkern) during spermatid development.
- Rescue experiments confirm the role of Merlin in male fertility.
Conclusions:
- Merlin mutations disrupt multiple critical stages of spermatogenesis in Drosophila.
- Merlin exhibits dynamic localization during meiosis and a novel mitochondrial localization in spermatids.
- Merlin likely plays a role in mitochondrial formation and function during male gamete development.
