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A functional genomic screen combined with time-lapse microscopy uncovers a novel set of genes involved in dorsal closure of Drosophila embryos.

Jankovics F, Henn L, Bujna Á, Vilmos P, Kiss N, Erdélyi M - PLoS ONE (2011)

Bottom Line: Morphogenesis, the establishment of the animal body, requires the coordinated rearrangement of cells and tissues regulated by a very strictly-determined genetic program.We show that pbl regulates actin accumulation and protrusion dynamics in the leading edge of the migrating epithelial cells.Finally, we provide evidence that pbl is involved in closure of the adult thorax, suggesting its general requirement in epithelial closure processes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary. jankovic@brc.hu

ABSTRACT
Morphogenesis, the establishment of the animal body, requires the coordinated rearrangement of cells and tissues regulated by a very strictly-determined genetic program. Dorsal closure of the epithelium in the Drosophila melanogaster embryo is one of the best models for such a complex morphogenetic event. To explore the genetic regulation of dorsal closure, we carried out a large-scale RNA interference-based screen in combination with in vivo time-lapse microscopy and identified several genes essential for the closure or affecting its dynamics. One of the novel dorsal closure genes, the small GTPase activator pebble (pbl), was selected for detailed analysis. We show that pbl regulates actin accumulation and protrusion dynamics in the leading edge of the migrating epithelial cells. In addition, pbl affects dorsal closure dynamics by regulating head involution, a morphogenetic process mechanically coupled with dorsal closure. Finally, we provide evidence that pbl is involved in closure of the adult thorax, suggesting its general requirement in epithelial closure processes.

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Related in: MedlinePlus

Protrusion dynamics in the DME cells of pbl mutants.(A and B) Frames of movie sequences showing DME cell protrusion dynamics in embryos expressing mCherry:Moe in engrailed-expressing cell stripes. Scale bars are 5 µm. (A) en-Gal4, UAS-mCherry:Moe control embryo. (B) Homozygous en-Gal4, UAS-mCherry:Moe; pbl3 embryo.
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pone-0022229-g010: Protrusion dynamics in the DME cells of pbl mutants.(A and B) Frames of movie sequences showing DME cell protrusion dynamics in embryos expressing mCherry:Moe in engrailed-expressing cell stripes. Scale bars are 5 µm. (A) en-Gal4, UAS-mCherry:Moe control embryo. (B) Homozygous en-Gal4, UAS-mCherry:Moe; pbl3 embryo.

Mentions: To test whether pbl is involved in the regulation of protrusion dynamics at the leading edge of the DME cells, in vivo time-lapse imaging of the pbl mutant embryos was performed. The actin-rich structures were visualized by expression of Moe:mCherry in the dorsal epithelium with the en-GAL4 driver. In agreement with the hystochemical observations, a weak accumulation of actin was detected at the leading edge of pbl mutant DME cells (Figure 10, Movie S7). During the zippering stage, both filopodia and lamellipodia were extended but the morphology of these protrusions were abnormal. In the pbl mutants protrusions were more extensive, filopodia were longer (4.8±1.4 µm in wild type [n = 58] versus 7.1±1.7 µm in pbl mutant embryos [n = 52]) and lamellipodia covered a larger protrusive area, reaching up to 26.6±7.3 µm2 (n = 12) compared to 14.5±4.0 µm2 (n = 13) in wild type. Despite of the abnormal protrusions in pbl mutants, towards the end of the closure process, DME cells engaged with cells from the opposite side and zippered the dorsal hole. These results indicate that reduction of pbl function affects actin accumulation and protrusion dynamics of the DME cells.


A functional genomic screen combined with time-lapse microscopy uncovers a novel set of genes involved in dorsal closure of Drosophila embryos.

Jankovics F, Henn L, Bujna Á, Vilmos P, Kiss N, Erdélyi M - PLoS ONE (2011)

Protrusion dynamics in the DME cells of pbl mutants.(A and B) Frames of movie sequences showing DME cell protrusion dynamics in embryos expressing mCherry:Moe in engrailed-expressing cell stripes. Scale bars are 5 µm. (A) en-Gal4, UAS-mCherry:Moe control embryo. (B) Homozygous en-Gal4, UAS-mCherry:Moe; pbl3 embryo.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3140500&req=5

pone-0022229-g010: Protrusion dynamics in the DME cells of pbl mutants.(A and B) Frames of movie sequences showing DME cell protrusion dynamics in embryos expressing mCherry:Moe in engrailed-expressing cell stripes. Scale bars are 5 µm. (A) en-Gal4, UAS-mCherry:Moe control embryo. (B) Homozygous en-Gal4, UAS-mCherry:Moe; pbl3 embryo.
Mentions: To test whether pbl is involved in the regulation of protrusion dynamics at the leading edge of the DME cells, in vivo time-lapse imaging of the pbl mutant embryos was performed. The actin-rich structures were visualized by expression of Moe:mCherry in the dorsal epithelium with the en-GAL4 driver. In agreement with the hystochemical observations, a weak accumulation of actin was detected at the leading edge of pbl mutant DME cells (Figure 10, Movie S7). During the zippering stage, both filopodia and lamellipodia were extended but the morphology of these protrusions were abnormal. In the pbl mutants protrusions were more extensive, filopodia were longer (4.8±1.4 µm in wild type [n = 58] versus 7.1±1.7 µm in pbl mutant embryos [n = 52]) and lamellipodia covered a larger protrusive area, reaching up to 26.6±7.3 µm2 (n = 12) compared to 14.5±4.0 µm2 (n = 13) in wild type. Despite of the abnormal protrusions in pbl mutants, towards the end of the closure process, DME cells engaged with cells from the opposite side and zippered the dorsal hole. These results indicate that reduction of pbl function affects actin accumulation and protrusion dynamics of the DME cells.

Bottom Line: Morphogenesis, the establishment of the animal body, requires the coordinated rearrangement of cells and tissues regulated by a very strictly-determined genetic program.We show that pbl regulates actin accumulation and protrusion dynamics in the leading edge of the migrating epithelial cells.Finally, we provide evidence that pbl is involved in closure of the adult thorax, suggesting its general requirement in epithelial closure processes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary. jankovic@brc.hu

ABSTRACT
Morphogenesis, the establishment of the animal body, requires the coordinated rearrangement of cells and tissues regulated by a very strictly-determined genetic program. Dorsal closure of the epithelium in the Drosophila melanogaster embryo is one of the best models for such a complex morphogenetic event. To explore the genetic regulation of dorsal closure, we carried out a large-scale RNA interference-based screen in combination with in vivo time-lapse microscopy and identified several genes essential for the closure or affecting its dynamics. One of the novel dorsal closure genes, the small GTPase activator pebble (pbl), was selected for detailed analysis. We show that pbl regulates actin accumulation and protrusion dynamics in the leading edge of the migrating epithelial cells. In addition, pbl affects dorsal closure dynamics by regulating head involution, a morphogenetic process mechanically coupled with dorsal closure. Finally, we provide evidence that pbl is involved in closure of the adult thorax, suggesting its general requirement in epithelial closure processes.

Show MeSH
Related in: MedlinePlus