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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

Dorsal open phenotypes generated by RNAi.RNAi phenotypes of genes in the phenotypic category I. Movie sequences show the absence of dorsal closure of dsRNA injected embryos expressing the ZCL0423 protein trap fusion protein. All embryos are shown in dorsal view with anterior to the left. Scale bar represents 50 µm.
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pone-0022229-g002: Dorsal open phenotypes generated by RNAi.RNAi phenotypes of genes in the phenotypic category I. Movie sequences show the absence of dorsal closure of dsRNA injected embryos expressing the ZCL0423 protein trap fusion protein. All embryos are shown in dorsal view with anterior to the left. Scale bar represents 50 µm.

Mentions: The identified genes were grouped into two phenotypic categories. In the first phenotypic group, dorsal closure is incomplete and the dorsal hole is not closed (Group I). Silencing of Notch (N), Bx42, shotgun (shg), scab (scb), canoe (cno), and CG6700 genes resulted in this phenotype (Figure 2, Movie S2). Loss-of-function mutations in N, shg, scb and cno have previously been shown to affect dorsal closure [26]–[29]. Silencing of these genes by RNAi phenocopies the previously-described abnormalities of the loss-of-function mutants indicating the specificity of our screening approach. In this phenotypic category, in addition to the four known genes, two novel genes, CG6700 and Bx42, were found to be involved in dorsal closure. Microinjection of dsRNA specific to CG6700 resulted in a severe closure defect (Figure 2, Movie S2). Closure was initiated, the straight movement front of the epithelium was formed, the opposing sheets approached the dorsal midline but some time later closure became arrested. CG6700 is a gene of unknown function and encodes a conserved protein containing a SAC3/GANP domain at the C-terminus. This domain has been shown to be present in proteins with diverse functions such as nuclear export factors (SAC3 of the budding yeast or mammalian GANP/MCM3-associated proteins), eukaryotic translation initiation factor 3 (eIF-3 p25), or regulators of the 26 S proteasome (Nin-1). None of these biological processes has previously been implicated in dorsal closure, thus detailed investigation of CG6700 may reveal additional mechanisms involved in this morphogenetic event.


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)

Dorsal open phenotypes generated by RNAi.RNAi phenotypes of genes in the phenotypic category I. Movie sequences show the absence of dorsal closure of dsRNA injected embryos expressing the ZCL0423 protein trap fusion protein. All embryos are shown in dorsal view with anterior to the left. Scale bar represents 50 µm.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0022229-g002: Dorsal open phenotypes generated by RNAi.RNAi phenotypes of genes in the phenotypic category I. Movie sequences show the absence of dorsal closure of dsRNA injected embryos expressing the ZCL0423 protein trap fusion protein. All embryos are shown in dorsal view with anterior to the left. Scale bar represents 50 µm.
Mentions: The identified genes were grouped into two phenotypic categories. In the first phenotypic group, dorsal closure is incomplete and the dorsal hole is not closed (Group I). Silencing of Notch (N), Bx42, shotgun (shg), scab (scb), canoe (cno), and CG6700 genes resulted in this phenotype (Figure 2, Movie S2). Loss-of-function mutations in N, shg, scb and cno have previously been shown to affect dorsal closure [26]–[29]. Silencing of these genes by RNAi phenocopies the previously-described abnormalities of the loss-of-function mutants indicating the specificity of our screening approach. In this phenotypic category, in addition to the four known genes, two novel genes, CG6700 and Bx42, were found to be involved in dorsal closure. Microinjection of dsRNA specific to CG6700 resulted in a severe closure defect (Figure 2, Movie S2). Closure was initiated, the straight movement front of the epithelium was formed, the opposing sheets approached the dorsal midline but some time later closure became arrested. CG6700 is a gene of unknown function and encodes a conserved protein containing a SAC3/GANP domain at the C-terminus. This domain has been shown to be present in proteins with diverse functions such as nuclear export factors (SAC3 of the budding yeast or mammalian GANP/MCM3-associated proteins), eukaryotic translation initiation factor 3 (eIF-3 p25), or regulators of the 26 S proteasome (Nin-1). None of these biological processes has previously been implicated in dorsal closure, thus detailed investigation of CG6700 may reveal additional mechanisms involved in this morphogenetic event.

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