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Loss of cofilin 1 disturbs actin dynamics, adhesion between enveloping and deep cell layers and cell movements during gastrulation in zebrafish.

Lin CW, Yen ST, Chang HT, Chen SJ, Lai SL, Liu YC, Chan TH, Liao WL, Lee SJ - PLoS ONE (2010)

Bottom Line: During gastrulation, cohesive migration drives associated cell layers to the completion of epiboly in zebrafish.Here, we examined the effect of malfunctioning actin turnover on the epibolic movement by knocking down an actin depolymerizing factor, cofilin 1, using antisense morpholino oligos (MO).The cfl1 MO-induced cell migration defect was found to be cell-autonomous in cell transplantation assays.

View Article: PubMed Central - PubMed

Affiliation: Institute of Zoology, National Taiwan University, Taipei, Taiwan, Republic of China.

ABSTRACT
During gastrulation, cohesive migration drives associated cell layers to the completion of epiboly in zebrafish. The association of different layers relies on E-cadherin based cellular junctions, whose stability can be affected by actin turnover. Here, we examined the effect of malfunctioning actin turnover on the epibolic movement by knocking down an actin depolymerizing factor, cofilin 1, using antisense morpholino oligos (MO). Knockdown of cfl1 interfered with epibolic movement of deep cell layer (DEL) but not in the enveloping layer (EVL) and the defect could be specifically rescued by overexpression of cfl1. It appeared that the uncoordinated movements of DEL and EVL were regulated by the differential expression of cfl1 in the DEL, but not EVL as shown by in situ hybridization. The dissociation of DEL and EVL was further evident by the loss of adhesion between layers by using transmission electronic and confocal microscopy analyses. cfl1 morphants also exhibited abnormal convergent extension, cellular migration and actin filaments, but not involution of hypoblast. The cfl1 MO-induced cell migration defect was found to be cell-autonomous in cell transplantation assays. These results suggest that proper actin turnover mediated by Cfl1 is essential for adhesion between DEL and EVL and cell movements during gastrulation in zebrafish.

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Related in: MedlinePlus

Live cell imaging reveals loose cell-cell interactions between the DEL and EVL in cfl1 morphants.Embryos injected with designated MOs and membrane-bound green fluorescent protein (GFP) mRNA, were dechorionated, immobilized, and examined by confocal microscopy for 10-min recordings at 10-s intervals per frame. The snapshots of representative embryos from the StdMO- (left column) or cfl1MO-injected embryos (right column) are shown. The recording times in minutes are denoted in the lower left corner of the left column. While StdMO-treated embryos showed continuous tight attachments between the DEL and EVL, DEL cells in cfl1 morphants did not form a tight connection with the EVL, which was further evidenced by the more-rounded cell shapes. Arrowheads indicate spaces between the EVL and DEL. A single-cell-thick EVL is to the right; yolk cells are toward the left; the animal pore is on the top; and the vegetal pore is at the bottom.
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pone-0015331-g007: Live cell imaging reveals loose cell-cell interactions between the DEL and EVL in cfl1 morphants.Embryos injected with designated MOs and membrane-bound green fluorescent protein (GFP) mRNA, were dechorionated, immobilized, and examined by confocal microscopy for 10-min recordings at 10-s intervals per frame. The snapshots of representative embryos from the StdMO- (left column) or cfl1MO-injected embryos (right column) are shown. The recording times in minutes are denoted in the lower left corner of the left column. While StdMO-treated embryos showed continuous tight attachments between the DEL and EVL, DEL cells in cfl1 morphants did not form a tight connection with the EVL, which was further evidenced by the more-rounded cell shapes. Arrowheads indicate spaces between the EVL and DEL. A single-cell-thick EVL is to the right; yolk cells are toward the left; the animal pore is on the top; and the vegetal pore is at the bottom.

Mentions: To further compare dynamic interactions between the DEL and EVL, we performed live imaging analysis of a gastrulating embryo from 7.5 to 8.5 hpf under confocal microscopy. We focused on the dorsolateral sites of embryos injected with membrane-bound GFP-GAP43 mRNAs and the StdMO or cfl1 tMO1. While both the DEL and EVL showed highly coordinated migration toward posterior sites in control embryos (Fig. 7, left column; Supplementary Movie S1), cells of the DEL in cfl1-morphants did not form tight attachments and showed a clear gap with EVL cells (Fig. 7, right column; Supplementary Movie S2). In addition, a very dynamic change in cell shape was observed in DEL cells of control embryos, but not in those of cfl1 morphants (Supplementary Movie S2).


Loss of cofilin 1 disturbs actin dynamics, adhesion between enveloping and deep cell layers and cell movements during gastrulation in zebrafish.

Lin CW, Yen ST, Chang HT, Chen SJ, Lai SL, Liu YC, Chan TH, Liao WL, Lee SJ - PLoS ONE (2010)

Live cell imaging reveals loose cell-cell interactions between the DEL and EVL in cfl1 morphants.Embryos injected with designated MOs and membrane-bound green fluorescent protein (GFP) mRNA, were dechorionated, immobilized, and examined by confocal microscopy for 10-min recordings at 10-s intervals per frame. The snapshots of representative embryos from the StdMO- (left column) or cfl1MO-injected embryos (right column) are shown. The recording times in minutes are denoted in the lower left corner of the left column. While StdMO-treated embryos showed continuous tight attachments between the DEL and EVL, DEL cells in cfl1 morphants did not form a tight connection with the EVL, which was further evidenced by the more-rounded cell shapes. Arrowheads indicate spaces between the EVL and DEL. A single-cell-thick EVL is to the right; yolk cells are toward the left; the animal pore is on the top; and the vegetal pore is at the bottom.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3008747&req=5

pone-0015331-g007: Live cell imaging reveals loose cell-cell interactions between the DEL and EVL in cfl1 morphants.Embryos injected with designated MOs and membrane-bound green fluorescent protein (GFP) mRNA, were dechorionated, immobilized, and examined by confocal microscopy for 10-min recordings at 10-s intervals per frame. The snapshots of representative embryos from the StdMO- (left column) or cfl1MO-injected embryos (right column) are shown. The recording times in minutes are denoted in the lower left corner of the left column. While StdMO-treated embryos showed continuous tight attachments between the DEL and EVL, DEL cells in cfl1 morphants did not form a tight connection with the EVL, which was further evidenced by the more-rounded cell shapes. Arrowheads indicate spaces between the EVL and DEL. A single-cell-thick EVL is to the right; yolk cells are toward the left; the animal pore is on the top; and the vegetal pore is at the bottom.
Mentions: To further compare dynamic interactions between the DEL and EVL, we performed live imaging analysis of a gastrulating embryo from 7.5 to 8.5 hpf under confocal microscopy. We focused on the dorsolateral sites of embryos injected with membrane-bound GFP-GAP43 mRNAs and the StdMO or cfl1 tMO1. While both the DEL and EVL showed highly coordinated migration toward posterior sites in control embryos (Fig. 7, left column; Supplementary Movie S1), cells of the DEL in cfl1-morphants did not form tight attachments and showed a clear gap with EVL cells (Fig. 7, right column; Supplementary Movie S2). In addition, a very dynamic change in cell shape was observed in DEL cells of control embryos, but not in those of cfl1 morphants (Supplementary Movie S2).

Bottom Line: During gastrulation, cohesive migration drives associated cell layers to the completion of epiboly in zebrafish.Here, we examined the effect of malfunctioning actin turnover on the epibolic movement by knocking down an actin depolymerizing factor, cofilin 1, using antisense morpholino oligos (MO).The cfl1 MO-induced cell migration defect was found to be cell-autonomous in cell transplantation assays.

View Article: PubMed Central - PubMed

Affiliation: Institute of Zoology, National Taiwan University, Taipei, Taiwan, Republic of China.

ABSTRACT
During gastrulation, cohesive migration drives associated cell layers to the completion of epiboly in zebrafish. The association of different layers relies on E-cadherin based cellular junctions, whose stability can be affected by actin turnover. Here, we examined the effect of malfunctioning actin turnover on the epibolic movement by knocking down an actin depolymerizing factor, cofilin 1, using antisense morpholino oligos (MO). Knockdown of cfl1 interfered with epibolic movement of deep cell layer (DEL) but not in the enveloping layer (EVL) and the defect could be specifically rescued by overexpression of cfl1. It appeared that the uncoordinated movements of DEL and EVL were regulated by the differential expression of cfl1 in the DEL, but not EVL as shown by in situ hybridization. The dissociation of DEL and EVL was further evident by the loss of adhesion between layers by using transmission electronic and confocal microscopy analyses. cfl1 morphants also exhibited abnormal convergent extension, cellular migration and actin filaments, but not involution of hypoblast. The cfl1 MO-induced cell migration defect was found to be cell-autonomous in cell transplantation assays. These results suggest that proper actin turnover mediated by Cfl1 is essential for adhesion between DEL and EVL and cell movements during gastrulation in zebrafish.

Show MeSH
Related in: MedlinePlus