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Filamin is required for ring canal assembly and actin organization during Drosophila oogenesis.

Li MG, Serr M, Edwards K, Ludmann S, Yamamoto D, Tilney LG, Field CM, Hays TS - J. Cell Biol. (1999)

Bottom Line: In consequence, actin-binding proteins are increasingly a focus of investigations into effectors of cell signaling and the coordination of cellular behaviors within developmental processes.Mutations in Drosophila filamin disrupt actin filament organization and compromise membrane integrity during oocyte development, resulting in female sterility.The genetic and molecular characterization of Drosophila filamin provides the first genetic model system for the analysis of filamin function and regulation during development.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Cell and Developmental Biology, University of Minnesota, St. Paul, Minnesota 55108, USA.

ABSTRACT
The remodeling of the actin cytoskeleton is essential for cell migration, cell division, and cell morphogenesis. Actin-binding proteins play a pivotal role in reorganizing the actin cytoskeleton in response to signals exchanged between cells. In consequence, actin-binding proteins are increasingly a focus of investigations into effectors of cell signaling and the coordination of cellular behaviors within developmental processes. One of the first actin-binding proteins identified was filamin, or actin-binding protein 280 (ABP280). Filamin is required for cell migration (Cunningham et al. 1992), and mutations in human alpha-filamin (FLN1; Fox et al. 1998) are responsible for impaired migration of cerebral neurons and give rise to periventricular heterotopia, a disorder that leads to epilepsy and vascular disorders, as well as embryonic lethality. We report the identification and characterization of a mutation in Drosophila filamin, the homologue of human alpha-filamin. During oogenesis, filamin is concentrated in the ring canal structures that fortify arrested cleavage furrows and establish cytoplasmic bridges between cells of the germline. The major structural features common to other filamins are conserved in Drosophila filamin. Mutations in Drosophila filamin disrupt actin filament organization and compromise membrane integrity during oocyte development, resulting in female sterility. The genetic and molecular characterization of Drosophila filamin provides the first genetic model system for the analysis of filamin function and regulation during development.

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Some intercellular transport functions are still intact in sko mutant ovaries. As late as stage 10, cytoplasmic dynein (a and b) and staufen (c and d) proteins show proper localization at the oocyte posterior in both wild-type (left) and mutant (right). At a similar stage, gurken mRNA is correctly located at the anterior margin of the oocyte (e, wild-type; f, sko).
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Figure 4: Some intercellular transport functions are still intact in sko mutant ovaries. As late as stage 10, cytoplasmic dynein (a and b) and staufen (c and d) proteins show proper localization at the oocyte posterior in both wild-type (left) and mutant (right). At a similar stage, gurken mRNA is correctly located at the anterior margin of the oocyte (e, wild-type; f, sko).

Mentions: To address the impact of sko on intercellular transport and cytoplasmic localization we examined the localization of RNAs and proteins known to be required for the proper development of the oocyte (Fig. 4). In previous work, we showed that cytoplasmic dynein accumulates within the presumptive oocyte, beginning very early in the germarium and continuing through later stages (Li et al. 1994). This pattern of dynein accumulation is also observed in sko mutant egg chambers, suggesting that the early slow phase of cytoplasmic transport from the nurse cell compartment to the oocyte before stage 9 is not disrupted. By stages 9 to 10 in wild-type egg chambers, dynein becomes concentrated within the oocyte at the posterior pole. In sko egg chambers, this posterior concentration of dynein in the oocyte also appears qualitatively normal. Similar to dynein, we find that the posterior accumulation of staufen protein and oskar mRNA in the oocyte does not depend on sko function. Furthermore, despite the distorted margin at the anterior of the oocyte, we still observe the typical anterior concentrations of both bicoid and gurken mRNAs in sko egg chambers.


Filamin is required for ring canal assembly and actin organization during Drosophila oogenesis.

Li MG, Serr M, Edwards K, Ludmann S, Yamamoto D, Tilney LG, Field CM, Hays TS - J. Cell Biol. (1999)

Some intercellular transport functions are still intact in sko mutant ovaries. As late as stage 10, cytoplasmic dynein (a and b) and staufen (c and d) proteins show proper localization at the oocyte posterior in both wild-type (left) and mutant (right). At a similar stage, gurken mRNA is correctly located at the anterior margin of the oocyte (e, wild-type; f, sko).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169474&req=5

Figure 4: Some intercellular transport functions are still intact in sko mutant ovaries. As late as stage 10, cytoplasmic dynein (a and b) and staufen (c and d) proteins show proper localization at the oocyte posterior in both wild-type (left) and mutant (right). At a similar stage, gurken mRNA is correctly located at the anterior margin of the oocyte (e, wild-type; f, sko).
Mentions: To address the impact of sko on intercellular transport and cytoplasmic localization we examined the localization of RNAs and proteins known to be required for the proper development of the oocyte (Fig. 4). In previous work, we showed that cytoplasmic dynein accumulates within the presumptive oocyte, beginning very early in the germarium and continuing through later stages (Li et al. 1994). This pattern of dynein accumulation is also observed in sko mutant egg chambers, suggesting that the early slow phase of cytoplasmic transport from the nurse cell compartment to the oocyte before stage 9 is not disrupted. By stages 9 to 10 in wild-type egg chambers, dynein becomes concentrated within the oocyte at the posterior pole. In sko egg chambers, this posterior concentration of dynein in the oocyte also appears qualitatively normal. Similar to dynein, we find that the posterior accumulation of staufen protein and oskar mRNA in the oocyte does not depend on sko function. Furthermore, despite the distorted margin at the anterior of the oocyte, we still observe the typical anterior concentrations of both bicoid and gurken mRNAs in sko egg chambers.

Bottom Line: In consequence, actin-binding proteins are increasingly a focus of investigations into effectors of cell signaling and the coordination of cellular behaviors within developmental processes.Mutations in Drosophila filamin disrupt actin filament organization and compromise membrane integrity during oocyte development, resulting in female sterility.The genetic and molecular characterization of Drosophila filamin provides the first genetic model system for the analysis of filamin function and regulation during development.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Cell and Developmental Biology, University of Minnesota, St. Paul, Minnesota 55108, USA.

ABSTRACT
The remodeling of the actin cytoskeleton is essential for cell migration, cell division, and cell morphogenesis. Actin-binding proteins play a pivotal role in reorganizing the actin cytoskeleton in response to signals exchanged between cells. In consequence, actin-binding proteins are increasingly a focus of investigations into effectors of cell signaling and the coordination of cellular behaviors within developmental processes. One of the first actin-binding proteins identified was filamin, or actin-binding protein 280 (ABP280). Filamin is required for cell migration (Cunningham et al. 1992), and mutations in human alpha-filamin (FLN1; Fox et al. 1998) are responsible for impaired migration of cerebral neurons and give rise to periventricular heterotopia, a disorder that leads to epilepsy and vascular disorders, as well as embryonic lethality. We report the identification and characterization of a mutation in Drosophila filamin, the homologue of human alpha-filamin. During oogenesis, filamin is concentrated in the ring canal structures that fortify arrested cleavage furrows and establish cytoplasmic bridges between cells of the germline. The major structural features common to other filamins are conserved in Drosophila filamin. Mutations in Drosophila filamin disrupt actin filament organization and compromise membrane integrity during oocyte development, resulting in female sterility. The genetic and molecular characterization of Drosophila filamin provides the first genetic model system for the analysis of filamin function and regulation during development.

Show MeSH
Related in: MedlinePlus