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Actin depolymerizing factors cofilin1 and destrin are required for ureteric bud branching morphogenesis.

Kuure S, Cebrian C, Machingo Q, Lu BC, Chi X, Hyink D, D'Agati V, Gurniak C, Witke W, Costantini F - PLoS Genet. (2010)

Bottom Line: The actin depolymerizing factors (ADFs) play important roles in several cellular processes that require cytoskeletal rearrangements, such as cell migration, but little is known about the in vivo functions of ADFs in developmental events like branching morphogenesis.Lack of Cfl1 and Dstn in the UB causes accumulation of filamentous actin, disruption of normal epithelial organization, and defects in cell migration.The results indicate that ADF activity, provided by either cofilin1 or destrin, is essential in UB epithelial cells for normal growth and branching.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics and Development, Columbia University Medical Center, New York, New York, United States of America.

ABSTRACT
The actin depolymerizing factors (ADFs) play important roles in several cellular processes that require cytoskeletal rearrangements, such as cell migration, but little is known about the in vivo functions of ADFs in developmental events like branching morphogenesis. While the molecular control of ureteric bud (UB) branching during kidney development has been extensively studied, the detailed cellular events underlying this process remain poorly understood. To gain insight into the role of actin cytoskeletal dynamics during renal branching morphogenesis, we studied the functional requirements for the closely related ADFs cofilin1 (Cfl1) and destrin (Dstn) during mouse development. Either deletion of Cfl1 in UB epithelium or an inactivating mutation in Dstn has no effect on renal morphogenesis, but simultaneous lack of both genes arrests branching morphogenesis at an early stage, revealing considerable functional overlap between cofilin1 and destrin. Lack of Cfl1 and Dstn in the UB causes accumulation of filamentous actin, disruption of normal epithelial organization, and defects in cell migration. Animals with less severe combinations of mutant Cfl1 and Dstn alleles, which retain one wild-type Cfl1 or Dstn allele, display abnormalities including ureter duplication, renal hypoplasia, and abnormal kidney shape. The results indicate that ADF activity, provided by either cofilin1 or destrin, is essential in UB epithelial cells for normal growth and branching.

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Kidney defects in Dstn−/− and Cfl1+/−;Dstn−/− mutant animals.Whole mount image (A) and histological section (B) of control kidneys. (C) Double ureter (asterisks) and duplex kidney formation in a Dstn−/− embryo. Arrow points to the cleft between the two lobes of the duplex kidney, and asterisks mark the two ureters. (D) Histology of Cfl1+/−;Dstn−/− kidney reveals irregular surface of the renal cortex. Arrows point to constriction sites, arrowhead to a dilated collecting duct. (E) and (F), Three-dimensional reconstruction from confocal optical sections of control kidney (Hoxb7/myrVenus;Cfl1+/−) (E), showing smooth surface and kidney shape, and Hoxb7/myrVenus;Cfl1+/−;Dstn−/− kidney (F), showing an irregular surface and abnormal cleft (arrow). (G) and (H), reduced kidney size in Cfl1+/−;Dstn−/− (H) compared to Dstn+/− control (G). The dotted curves indicate the outlines of the two control kidneys. All kidneys are at E16.5, except C which is E17.5.
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pgen-1001176-g001: Kidney defects in Dstn−/− and Cfl1+/−;Dstn−/− mutant animals.Whole mount image (A) and histological section (B) of control kidneys. (C) Double ureter (asterisks) and duplex kidney formation in a Dstn−/− embryo. Arrow points to the cleft between the two lobes of the duplex kidney, and asterisks mark the two ureters. (D) Histology of Cfl1+/−;Dstn−/− kidney reveals irregular surface of the renal cortex. Arrows point to constriction sites, arrowhead to a dilated collecting duct. (E) and (F), Three-dimensional reconstruction from confocal optical sections of control kidney (Hoxb7/myrVenus;Cfl1+/−) (E), showing smooth surface and kidney shape, and Hoxb7/myrVenus;Cfl1+/−;Dstn−/− kidney (F), showing an irregular surface and abnormal cleft (arrow). (G) and (H), reduced kidney size in Cfl1+/−;Dstn−/− (H) compared to Dstn+/− control (G). The dotted curves indicate the outlines of the two control kidneys. All kidneys are at E16.5, except C which is E17.5.

Mentions: Cfl1 and Dstn are both expressed in most or all cells of the developing kidney, while Cfl2 is apparently not expressed in kidney [18]. In order to investigate the requirement for ADF activity in ureteric bud morphogenesis, we studied the effects Dstn and Cfl1 mutations during renal development, initially using conventional loss-of function alleles. For Dstn, we used the Dstncorn1-2J mutant allele, which is phenotypically similar to the knockout allele [5], [6] and we therefore refer to Dstncorn1-2J heterozygotes and homozygotes as Dstn+/− and Dstn−/−. We observed no renal or ureteric abnormalities in Cfl1+/− or Dstn+/− heterozygotes (Figure 1A and 1B, and Figure 2A, 2C, 2E, 2G), or in Dstn+/−;Cfl1+/− compound heterozygotes (Table 1, column 3). Twenty-three percent of Dstn−/− embryos displayed a duplicated ureter, sometimes resulting in a duplex kidney (Table 1, column 1; Figure 1C, Figure S1A, S1B), but renal development appeared otherwise normal (data not shown). Surprisingly, none of the twenty-one Cfl1+/−;Dstn−/− embryos we examined displayed ureter duplications (Table 1, column 4), but instead 38% had kidneys that were abnormally shaped, elongated and uneven on the surface (Figure 1D, 1F), while an additional 29% had mildly hypoplastic kidneys (approximately 25% reduced in size, e.g., Figure 1H). Cultures of E12.5 Cfl1+/−;Dstn−/− renal explants sometimes showed a slight delay in branching, resulting in reduced UB tip numbers, but no obvious branching pattern abnormalities that might explain the abnormal kidney shapes were observed (Figure S1C, S1D, S1E, S1F). It is not clear why removing one Cfl1 allele would apparently rescue the ureteric duplications seen in some Dstn−/− mutants, but this may be a consequence of the mixed genetic background. Overall, however, the spectrum of ureteric and mild renal abnormalities observed in some Dstn−/− and Cfl1+/−;Dstn−/− kidneys suggests a role for actin depolymerization during renal branching morphogenesis.


Actin depolymerizing factors cofilin1 and destrin are required for ureteric bud branching morphogenesis.

Kuure S, Cebrian C, Machingo Q, Lu BC, Chi X, Hyink D, D'Agati V, Gurniak C, Witke W, Costantini F - PLoS Genet. (2010)

Kidney defects in Dstn−/− and Cfl1+/−;Dstn−/− mutant animals.Whole mount image (A) and histological section (B) of control kidneys. (C) Double ureter (asterisks) and duplex kidney formation in a Dstn−/− embryo. Arrow points to the cleft between the two lobes of the duplex kidney, and asterisks mark the two ureters. (D) Histology of Cfl1+/−;Dstn−/− kidney reveals irregular surface of the renal cortex. Arrows point to constriction sites, arrowhead to a dilated collecting duct. (E) and (F), Three-dimensional reconstruction from confocal optical sections of control kidney (Hoxb7/myrVenus;Cfl1+/−) (E), showing smooth surface and kidney shape, and Hoxb7/myrVenus;Cfl1+/−;Dstn−/− kidney (F), showing an irregular surface and abnormal cleft (arrow). (G) and (H), reduced kidney size in Cfl1+/−;Dstn−/− (H) compared to Dstn+/− control (G). The dotted curves indicate the outlines of the two control kidneys. All kidneys are at E16.5, except C which is E17.5.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2965756&req=5

pgen-1001176-g001: Kidney defects in Dstn−/− and Cfl1+/−;Dstn−/− mutant animals.Whole mount image (A) and histological section (B) of control kidneys. (C) Double ureter (asterisks) and duplex kidney formation in a Dstn−/− embryo. Arrow points to the cleft between the two lobes of the duplex kidney, and asterisks mark the two ureters. (D) Histology of Cfl1+/−;Dstn−/− kidney reveals irregular surface of the renal cortex. Arrows point to constriction sites, arrowhead to a dilated collecting duct. (E) and (F), Three-dimensional reconstruction from confocal optical sections of control kidney (Hoxb7/myrVenus;Cfl1+/−) (E), showing smooth surface and kidney shape, and Hoxb7/myrVenus;Cfl1+/−;Dstn−/− kidney (F), showing an irregular surface and abnormal cleft (arrow). (G) and (H), reduced kidney size in Cfl1+/−;Dstn−/− (H) compared to Dstn+/− control (G). The dotted curves indicate the outlines of the two control kidneys. All kidneys are at E16.5, except C which is E17.5.
Mentions: Cfl1 and Dstn are both expressed in most or all cells of the developing kidney, while Cfl2 is apparently not expressed in kidney [18]. In order to investigate the requirement for ADF activity in ureteric bud morphogenesis, we studied the effects Dstn and Cfl1 mutations during renal development, initially using conventional loss-of function alleles. For Dstn, we used the Dstncorn1-2J mutant allele, which is phenotypically similar to the knockout allele [5], [6] and we therefore refer to Dstncorn1-2J heterozygotes and homozygotes as Dstn+/− and Dstn−/−. We observed no renal or ureteric abnormalities in Cfl1+/− or Dstn+/− heterozygotes (Figure 1A and 1B, and Figure 2A, 2C, 2E, 2G), or in Dstn+/−;Cfl1+/− compound heterozygotes (Table 1, column 3). Twenty-three percent of Dstn−/− embryos displayed a duplicated ureter, sometimes resulting in a duplex kidney (Table 1, column 1; Figure 1C, Figure S1A, S1B), but renal development appeared otherwise normal (data not shown). Surprisingly, none of the twenty-one Cfl1+/−;Dstn−/− embryos we examined displayed ureter duplications (Table 1, column 4), but instead 38% had kidneys that were abnormally shaped, elongated and uneven on the surface (Figure 1D, 1F), while an additional 29% had mildly hypoplastic kidneys (approximately 25% reduced in size, e.g., Figure 1H). Cultures of E12.5 Cfl1+/−;Dstn−/− renal explants sometimes showed a slight delay in branching, resulting in reduced UB tip numbers, but no obvious branching pattern abnormalities that might explain the abnormal kidney shapes were observed (Figure S1C, S1D, S1E, S1F). It is not clear why removing one Cfl1 allele would apparently rescue the ureteric duplications seen in some Dstn−/− mutants, but this may be a consequence of the mixed genetic background. Overall, however, the spectrum of ureteric and mild renal abnormalities observed in some Dstn−/− and Cfl1+/−;Dstn−/− kidneys suggests a role for actin depolymerization during renal branching morphogenesis.

Bottom Line: The actin depolymerizing factors (ADFs) play important roles in several cellular processes that require cytoskeletal rearrangements, such as cell migration, but little is known about the in vivo functions of ADFs in developmental events like branching morphogenesis.Lack of Cfl1 and Dstn in the UB causes accumulation of filamentous actin, disruption of normal epithelial organization, and defects in cell migration.The results indicate that ADF activity, provided by either cofilin1 or destrin, is essential in UB epithelial cells for normal growth and branching.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics and Development, Columbia University Medical Center, New York, New York, United States of America.

ABSTRACT
The actin depolymerizing factors (ADFs) play important roles in several cellular processes that require cytoskeletal rearrangements, such as cell migration, but little is known about the in vivo functions of ADFs in developmental events like branching morphogenesis. While the molecular control of ureteric bud (UB) branching during kidney development has been extensively studied, the detailed cellular events underlying this process remain poorly understood. To gain insight into the role of actin cytoskeletal dynamics during renal branching morphogenesis, we studied the functional requirements for the closely related ADFs cofilin1 (Cfl1) and destrin (Dstn) during mouse development. Either deletion of Cfl1 in UB epithelium or an inactivating mutation in Dstn has no effect on renal morphogenesis, but simultaneous lack of both genes arrests branching morphogenesis at an early stage, revealing considerable functional overlap between cofilin1 and destrin. Lack of Cfl1 and Dstn in the UB causes accumulation of filamentous actin, disruption of normal epithelial organization, and defects in cell migration. Animals with less severe combinations of mutant Cfl1 and Dstn alleles, which retain one wild-type Cfl1 or Dstn allele, display abnormalities including ureter duplication, renal hypoplasia, and abnormal kidney shape. The results indicate that ADF activity, provided by either cofilin1 or destrin, is essential in UB epithelial cells for normal growth and branching.

Show MeSH
Related in: MedlinePlus