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Daniel Louvard - One of the best experts on this subject based on the ideXlab platform.
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enterocyte loss of polarity and gut wound healing rely upon the f actin severing function of Villin
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Florent Ubelmann, Mathias Chamaillard, Fatima Elmarjou, Anthony Simon, Jeanne Netter, Danijela Vignjevic, Buford L Nichols, Roberto Quezadacalvillo, Teddy Grandjean, Daniel LouvardAbstract:Efficient wound healing is required to maintain the integrity of the intestinal epithelial barrier because of its constant exposure to a large variety of environmental stresses. This process implies a partial cell depolarization and the acquisition of a motile phenotype that involves rearrangements of the actin cytoskeleton. Here we address how polarized enterocytes harboring actin-rich apical microvilli undergo extensive cell remodeling to drive injury repair. Using live imaging technologies, we demonstrate that enterocytes in vitro and in vivo rapidly depolarize their microvilli at the wound edge. Through its F-actin–severing activity, the microvillar actin-binding protein Villin drives both apical microvilli disassembly in vitro and in vivo and promotes lamellipodial extension. Photoactivation experiments indicate that microvillar actin is mobilized at the lamellipodium, allowing optimal migration. Finally, efficient repair of colonic mechanical injuries requires Villin severing of F-actin, emphasizing the importance of Villin function in intestinal homeostasis. Thus, Villin severs F-actin to ensure microvillus depolarization and enterocyte remodeling upon injury. This work highlights the importance of specialized apical pole disassembly for the repolarization of epithelial cells initiating migration.
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Sequence of Human ViUin: a Large Duplicated Domain Homologous with Other Actin-severing Proteins and a Unique Small Carboxy-terminal Domain Related to Villin Specificity
2013Co-Authors: Monique Arpin, Joelle Finidori, Eric Pringault, Alphonse Garcia, J M Jeltsch, Daniel LouvardAbstract:Abstract. Villin is a calcium-regulated actin-binding protein that caps, severs, and bundles actin filaments in vitro. This 92,500-D protein is a major constituent of the actin bundles within the microvilli of the brush border surface of intestinal and kidney proximal tubule cells. Villin is a very early marker of cells involved in absorption and its expression is highly increased during intestinal cell differentiation. The amino acid sequence deduced from the cDNA sequence revealed that human Villin is composed of three domains. The first two domains appear as the result of a duplication: their structural organization is similar. We can then define a basic unit in which a slightly hydrophilic motif is followed by three hydrophobic motifs, similar between themselves and regularl
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Plastin 1 binds to keratin and is required for terminal web assembly in the intestinal epithelium.
Molecular biology of the cell, 2009Co-Authors: Eva-maria S. Grimm-günter, Céline Revenu, Sonia Ramos, Ilse Hurbain, Neil Smyth, Evelyne Ferrary, Daniel Louvard, Sylvie Robine, Francisco RiveroAbstract:Plastin 1 (I-plastin, fimbrin) along with Villin and espin is a prominent actin-bundling protein of the intestinal brush border microvilli. We demonstrate here that plastin 1 accumulates in the terminal web and interacts with keratin 19, possibly contributing to anchoring the rootlets to the keratin network. This prompted us to investigate the importance of plastin 1 in brush border assembly. Although in vivo neither Villin nor espin is required for brush border structure, plastin 1-deficient mice have conspicuous ultrastructural alterations: microvilli are shorter and constricted at their base, and, strikingly, their core actin bundles lack true rootlets. The composition of the microvilli themselves is apparently normal, whereas that of the terminal web is profoundly altered. Although the plastin 1 knockout mice do not show any overt gross phenotype and present a normal intestinal microanatomy, the alterations result in increased fragility of the epithelium. This is seen as an increased sensitivity of the brush border to biochemical manipulations, decreased transepithelial resistance, and increased sensitivity to dextran sodium sulfate-induced colitis. Plastin 1 thus emerges as an important regulator of brush border morphology and stability through a novel role in the organization of the terminal web, possibly by connecting actin filaments to the underlying intermediate filament network.
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Plastin 1 Binds to Keratin and Is Required for Terminal Web Assembly in the Intestinal Epithelium
2008Co-Authors: Eva-maria S. Grimm-günter, Céline Revenu, Sonia Ramos, Ilse Hurbain, Neil Smyth, Evelyne Ferrary, Daniel Louvard, Sylvie Robine, Francisco Rivero, Thomas D. PollardAbstract:Plastin 1 (I-plastin, fimbrin) along with Villin and espin is a prominent actin-bundling protein of the intestinal brush border microvilli. We demonstrate here that plastin 1 accumulates in the terminal web and interacts with keratin 19, possibly contributing to anchoring the rootlets to the keratin network. This prompted us to investigate the importance of plastin 1 in brush border assembly. Although in vivo neither Villin nor espin is required for brush border structure, plastin 1-deficient mice have conspicuous ultrastructural alterations: microvilli are shorter and constricted at their base, and, strikingly, their core actin bundles lack true rootlets. The composition of the microvilli themselves is apparently normal, whereas that of the terminal web is profoundly altered. Although the plastin 1 knockout mice do not show any overt gross phenotype and present a normal intestinal microanatomy, the alterations result in increased fragility of the epithelium. This is seen as an increased sensitivity of the brush border to biochemical manipulations, decreased transepithelial resistance, and increased sensitivity to dextran sodium sulfate-induced colitis. Plastin 1 thus emerges as an important regulator of brush border morphology and stability through a novel role in the organization of the termina
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tissue specific and inducible cre mediated recombination in the gut epithelium
Genesis, 2004Co-Authors: Fatima El Marjou, Daniel Louvard, Klauspeter Janssen, Benny Hungjunn Chang, Valerie Hindie, Lawrence Chan, Pierre Chambon, Daniel Metzger, Sylvie RobineAbstract:We generated two complementary systems for Cre-mediated recombination of target genes in the mouse digestive epithelium and tested them with a Cre-reporter mouse strain. Cre was expressed under the control of a 9 kb regulatory region of the murine Villin gene (vil-Cre). Genetic recombination was initiated at embryonic day (E) 9 in the visceral endoderm, and by E12.5 in the entire intestinal epithelium, but not in other tissues. Cre expression was maintained throughout adulthood. Furthermore, transgenic mice bearing a tamoxifen-dependent Cre recombinase (vil-Cre-ERT2) expressed under the control of the Villin promoter were created to perform targeted spatiotemporally controlled somatic recombination. After tamoxifen treatment, recombination was detectable throughout the digestive epithelium. The recombined locus persisted for 60 days after tamoxifen administration, despite rapid intestinal cell renewal, indicating that epithelial progenitor cells had been targeted. The Villin-Cre and Villin-Cre-ERT2 mice provide valuable tools for studies of cell lineage allocation and gene function in the developing and adult intestine.
Deborah L Gumucio - One of the best experts on this subject based on the ideXlab platform.
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cis elements of the Villin gene control expression in restricted domains of the vertical crypt and horizontal duodenum cecum axes of the intestine
Journal of Biological Chemistry, 2002Co-Authors: Blair B Madison, Laura Dunbar, Xiaotan T Qiao, Katherine Braunstein, Evan M Braunstein, Deborah L GumucioAbstract:Abstract Villin, an actin bundling protein found in the apical brush border of absorptive tissues, is one of the first structural genes to be transcriptionally activated in the embryonic intestinal endoderm. In the adult, Villin is broadly expressed in every cell of the intestinal epithelium on both the vertical axis (crypt to villus tip) and the horizontal axis (duodenum through colon) of the intestine. Here, we document that a 12.4-kilobase region of the mouse Villin gene drives high level expression of two different reporter genes (LacZ and Cre recombinase) within the entire intestinal epithelium of transgenic mice. Deletion of a portion of this transgene results in reduction of β-galactosidase activity in restricted domains of the small intestine (duodenum) and large intestine (cecum). In addition, expression is reduced in the crypt compartment throughout the intestine. Thus, the global expression pattern of Villin in the intestine is apparently the consequence of an amalgam of distinct and individual domain-specific control processes. That is, expression of Villin in the duodenum and cecum requires different regulatory sequences than the rest of the intestine, and the expression of Villin in crypts is regulated by different circuitry than expression of Villin on villus tips.
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cis elements of the Villin gene control expression in restricted domains of the vertical crypt and horizontal duodenum cecum axes of the intestine
Journal of Biological Chemistry, 2002Co-Authors: Blair B Madison, Laura Dunbar, Xiaotan T Qiao, Katherine Braunstein, Evan M Braunstein, Deborah L GumucioAbstract:Villin, an actin bundling protein found in the apical brush border of absorptive tissues, is one of the first structural genes to be transcriptionally activated in the embryonic intestinal endoderm. In the adult, Villin is broadly expressed in every cell of the intestinal epithelium on both the vertical axis (crypt to villus tip) and the horizontal axis (duodenum through colon) of the intestine. Here, we document that a 12.4-kilobase region of the mouse Villin gene drives high level expression of two different reporter genes (LacZ and Cre recombinase) within the entire intestinal epithelium of transgenic mice. Deletion of a portion of this transgene results in reduction of beta-galactosidase activity in restricted domains of the small intestine (duodenum) and large intestine (cecum). In addition, expression is reduced in the crypt compartment throughout the intestine. Thus, the global expression pattern of Villin in the intestine is apparently the consequence of an amalgam of distinct and individual domain-specific control processes. That is, expression of Villin in the duodenum and cecum requires different regulatory sequences than the rest of the intestine, and the expression of Villin in crypts is regulated by different circuitry than expression of Villin on villus tips.
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targeted disruption of the mouse Villin gene does not impair the morphogenesis of microvilli
Developmental Dynamics, 1998Co-Authors: Kathleen I Pinson, Linda C. Samuelson, Laura Dunbar, Deborah L GumucioAbstract:The small intestine is function- ally dependent on the presence of the brush border, a tightly packed array of microvilli that forms the amplified apical surface of absorptive cells. In the core of each microvillus, actin fila- ments are bundled by two proteins, Villin and fimbrin. Previous in vitro studies using antisense approaches indicated that Villin plays an impor- tant role in the morphogenesis of microvilli. To examine the in vivo consequences of Villin defi- ciency, we disrupted the mouse Villin gene by targeted recombination in mouse embryonic stem cells. A b-galactosidase cDNA was also introduced into the Villin locus by the targeting event. Homo- zygous Villin-deficient mice are viable, fertile, and display no gross abnormalities. Intact micro- villi are present in the small intestine, colon, kidney proximal tubules, and liver bile cana- liculi. Although subtle ultrastructural abnormali- ties can be detected in the actin cores of small intestinal microvilli, localization of sucrase iso- maltase, brush border myosin I, and zonula oc- cludens I to the microvillar surface of the small intestine is normal. Thus, in vivo, Villin plays a minor or redundant role in the generation of microvilli in multiple absorptive tissues. Dev. Dyn. 1998;211:109-121.
Sylvie Robine - One of the best experts on this subject based on the ideXlab platform.
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Plastin 1 binds to keratin and is required for terminal web assembly in the intestinal epithelium.
Molecular biology of the cell, 2009Co-Authors: Eva-maria S. Grimm-günter, Céline Revenu, Sonia Ramos, Ilse Hurbain, Neil Smyth, Evelyne Ferrary, Daniel Louvard, Sylvie Robine, Francisco RiveroAbstract:Plastin 1 (I-plastin, fimbrin) along with Villin and espin is a prominent actin-bundling protein of the intestinal brush border microvilli. We demonstrate here that plastin 1 accumulates in the terminal web and interacts with keratin 19, possibly contributing to anchoring the rootlets to the keratin network. This prompted us to investigate the importance of plastin 1 in brush border assembly. Although in vivo neither Villin nor espin is required for brush border structure, plastin 1-deficient mice have conspicuous ultrastructural alterations: microvilli are shorter and constricted at their base, and, strikingly, their core actin bundles lack true rootlets. The composition of the microvilli themselves is apparently normal, whereas that of the terminal web is profoundly altered. Although the plastin 1 knockout mice do not show any overt gross phenotype and present a normal intestinal microanatomy, the alterations result in increased fragility of the epithelium. This is seen as an increased sensitivity of the brush border to biochemical manipulations, decreased transepithelial resistance, and increased sensitivity to dextran sodium sulfate-induced colitis. Plastin 1 thus emerges as an important regulator of brush border morphology and stability through a novel role in the organization of the terminal web, possibly by connecting actin filaments to the underlying intermediate filament network.
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Plastin 1 Binds to Keratin and Is Required for Terminal Web Assembly in the Intestinal Epithelium
2008Co-Authors: Eva-maria S. Grimm-günter, Céline Revenu, Sonia Ramos, Ilse Hurbain, Neil Smyth, Evelyne Ferrary, Daniel Louvard, Sylvie Robine, Francisco Rivero, Thomas D. PollardAbstract:Plastin 1 (I-plastin, fimbrin) along with Villin and espin is a prominent actin-bundling protein of the intestinal brush border microvilli. We demonstrate here that plastin 1 accumulates in the terminal web and interacts with keratin 19, possibly contributing to anchoring the rootlets to the keratin network. This prompted us to investigate the importance of plastin 1 in brush border assembly. Although in vivo neither Villin nor espin is required for brush border structure, plastin 1-deficient mice have conspicuous ultrastructural alterations: microvilli are shorter and constricted at their base, and, strikingly, their core actin bundles lack true rootlets. The composition of the microvilli themselves is apparently normal, whereas that of the terminal web is profoundly altered. Although the plastin 1 knockout mice do not show any overt gross phenotype and present a normal intestinal microanatomy, the alterations result in increased fragility of the epithelium. This is seen as an increased sensitivity of the brush border to biochemical manipulations, decreased transepithelial resistance, and increased sensitivity to dextran sodium sulfate-induced colitis. Plastin 1 thus emerges as an important regulator of brush border morphology and stability through a novel role in the organization of the termina
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tissue specific and inducible cre mediated recombination in the gut epithelium
Genesis, 2004Co-Authors: Fatima El Marjou, Daniel Louvard, Klauspeter Janssen, Benny Hungjunn Chang, Valerie Hindie, Lawrence Chan, Pierre Chambon, Daniel Metzger, Sylvie RobineAbstract:We generated two complementary systems for Cre-mediated recombination of target genes in the mouse digestive epithelium and tested them with a Cre-reporter mouse strain. Cre was expressed under the control of a 9 kb regulatory region of the murine Villin gene (vil-Cre). Genetic recombination was initiated at embryonic day (E) 9 in the visceral endoderm, and by E12.5 in the entire intestinal epithelium, but not in other tissues. Cre expression was maintained throughout adulthood. Furthermore, transgenic mice bearing a tamoxifen-dependent Cre recombinase (vil-Cre-ERT2) expressed under the control of the Villin promoter were created to perform targeted spatiotemporally controlled somatic recombination. After tamoxifen treatment, recombination was detectable throughout the digestive epithelium. The recombined locus persisted for 60 days after tamoxifen administration, despite rapid intestinal cell renewal, indicating that epithelial progenitor cells had been targeted. The Villin-Cre and Villin-Cre-ERT2 mice provide valuable tools for studies of cell lineage allocation and gene function in the developing and adult intestine.
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regulatory sequences of the mouse Villin gene that efficiently drive transgenic expression in immature and differentiated epithelial cells of small and large intestines
Journal of Biological Chemistry, 1999Co-Authors: Daniel Pinto, Sylvie Robine, Frederic Jaisser, El F Marjou, Daniel LouvardAbstract:Abstract Villin is an early marker of epithelial cells from the digestive and urogenital tracts. Indeed Villin is expressed in the stem cells and the proliferative cells of the intestinal crypts. To investigate the underlying molecular mechanisms and particularly those responsible for the restricted tissue specificity, a large genomic region of the mouse Villin gene has been analyzed. A 9-kilobase (kb) regulatory region of the mouse Villin gene (harboring 3.5 kb upstream the transcription start site and 5.5 kb of the first intron) was able to promote transcription of the LacZ reporter gene in the small and large intestines of transgenic mice, in a transmissible manner, and thus efficiently directed subsequent β-galactosidase expression in epithelial cells along the entire crypt-villus axis. In the kidney, the transgene was also expressed in the epithelial cells of the proximal tubules but is likely sensitive to the site of integration. A construct lacking the first intron restricted β-galactosidase expression to the small intestine. Thus, the 9-kb genomic region contains the necessary cis-acting elements to recapitulate the tissue-specific expression pattern of the endogenous Villin gene. Hence, these regulatory sequences can be used to target heterologous genes in immature and differentiated epithelial cells of the small and/or large intestinal mucosa.
Laura Dunbar - One of the best experts on this subject based on the ideXlab platform.
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cis elements of the Villin gene control expression in restricted domains of the vertical crypt and horizontal duodenum cecum axes of the intestine
Journal of Biological Chemistry, 2002Co-Authors: Blair B Madison, Laura Dunbar, Xiaotan T Qiao, Katherine Braunstein, Evan M Braunstein, Deborah L GumucioAbstract:Abstract Villin, an actin bundling protein found in the apical brush border of absorptive tissues, is one of the first structural genes to be transcriptionally activated in the embryonic intestinal endoderm. In the adult, Villin is broadly expressed in every cell of the intestinal epithelium on both the vertical axis (crypt to villus tip) and the horizontal axis (duodenum through colon) of the intestine. Here, we document that a 12.4-kilobase region of the mouse Villin gene drives high level expression of two different reporter genes (LacZ and Cre recombinase) within the entire intestinal epithelium of transgenic mice. Deletion of a portion of this transgene results in reduction of β-galactosidase activity in restricted domains of the small intestine (duodenum) and large intestine (cecum). In addition, expression is reduced in the crypt compartment throughout the intestine. Thus, the global expression pattern of Villin in the intestine is apparently the consequence of an amalgam of distinct and individual domain-specific control processes. That is, expression of Villin in the duodenum and cecum requires different regulatory sequences than the rest of the intestine, and the expression of Villin in crypts is regulated by different circuitry than expression of Villin on villus tips.
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cis elements of the Villin gene control expression in restricted domains of the vertical crypt and horizontal duodenum cecum axes of the intestine
Journal of Biological Chemistry, 2002Co-Authors: Blair B Madison, Laura Dunbar, Xiaotan T Qiao, Katherine Braunstein, Evan M Braunstein, Deborah L GumucioAbstract:Villin, an actin bundling protein found in the apical brush border of absorptive tissues, is one of the first structural genes to be transcriptionally activated in the embryonic intestinal endoderm. In the adult, Villin is broadly expressed in every cell of the intestinal epithelium on both the vertical axis (crypt to villus tip) and the horizontal axis (duodenum through colon) of the intestine. Here, we document that a 12.4-kilobase region of the mouse Villin gene drives high level expression of two different reporter genes (LacZ and Cre recombinase) within the entire intestinal epithelium of transgenic mice. Deletion of a portion of this transgene results in reduction of beta-galactosidase activity in restricted domains of the small intestine (duodenum) and large intestine (cecum). In addition, expression is reduced in the crypt compartment throughout the intestine. Thus, the global expression pattern of Villin in the intestine is apparently the consequence of an amalgam of distinct and individual domain-specific control processes. That is, expression of Villin in the duodenum and cecum requires different regulatory sequences than the rest of the intestine, and the expression of Villin in crypts is regulated by different circuitry than expression of Villin on villus tips.
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targeted disruption of the mouse Villin gene does not impair the morphogenesis of microvilli
Developmental Dynamics, 1998Co-Authors: Kathleen I Pinson, Linda C. Samuelson, Laura Dunbar, Deborah L GumucioAbstract:The small intestine is function- ally dependent on the presence of the brush border, a tightly packed array of microvilli that forms the amplified apical surface of absorptive cells. In the core of each microvillus, actin fila- ments are bundled by two proteins, Villin and fimbrin. Previous in vitro studies using antisense approaches indicated that Villin plays an impor- tant role in the morphogenesis of microvilli. To examine the in vivo consequences of Villin defi- ciency, we disrupted the mouse Villin gene by targeted recombination in mouse embryonic stem cells. A b-galactosidase cDNA was also introduced into the Villin locus by the targeting event. Homo- zygous Villin-deficient mice are viable, fertile, and display no gross abnormalities. Intact micro- villi are present in the small intestine, colon, kidney proximal tubules, and liver bile cana- liculi. Although subtle ultrastructural abnormali- ties can be detected in the actin cores of small intestinal microvilli, localization of sucrase iso- maltase, brush border myosin I, and zonula oc- cludens I to the microvillar surface of the small intestine is normal. Thus, in vivo, Villin plays a minor or redundant role in the generation of microvilli in multiple absorptive tissues. Dev. Dyn. 1998;211:109-121.
Shanjin Huang - One of the best experts on this subject based on the ideXlab platform.
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arabidopsis Villins promote actin turnover at pollen tube tips and facilitate the construction of actin collars
The Plant Cell, 2013Co-Authors: Xiaolu Qu, Juan Wang, Hua Zhang, Naizhi Chen, Shanjin HuangAbstract:Apical actin filaments are crucial for pollen tube tip growth. However, the specific dynamic changes and regulatory mechanisms associated with actin filaments in the apical region remain largely unknown. Here, we have investigated the quantitative dynamic parameters that underlie actin filament growth and disappearance in the apical regions of pollen tubes and identified Villin as the major player that drives rapid turnover of actin filaments in this region. Downregulation of Arabidopsis thaliana Villin2 (VLN2) and VLN5 led to accumulation of actin filaments at the pollen tube apex. Careful analysis of single filament dynamics showed that the severing frequency significantly decreased, and the lifetime significantly increased in vln2 vln5 pollen tubes. These results indicate that Villin-mediated severing is critical for turnover and departure of actin filaments originating in the apical region. Consequently, the construction of actin collars was affected in vln2 vln5 pollen tubes. In addition to the decrease in severing frequency, actin filaments also became wavy and buckled in the apical cytoplasm of vln2 vln5 pollen tubes. These results suggest that Villin confers rigidity upon actin filaments. Furthermore, an observed decrease in skewness of actin filaments in the subapical region of vln2 vln5 pollen tubes suggests that Villin-mediated bundling activity may also play a role in the construction of actin collars. Thus, our data suggest that Villins promote actin turnover at pollen tube tips and facilitate the construction of actin collars.
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Arabidopsis Villin5, an actin filament bundling and severing protein, is necessary for normal pollen tube growth.
The Plant cell, 2010Co-Authors: Hua Zhang, Yurong Xie, Naizhi Chen, Chanchan Bao, Parul Khurana, Qiannan Wang, Yiyan Zheng, Laurent Blanchoin, Christopher J Staiger, Shanjin HuangAbstract:A dynamic actin cytoskeleton is essential for pollen germination and tube growth. However, the molecular mechanisms underlying the organization and turnover of the actin cytoskeleton in pollen remain poorly understood. Villin plays a key role in the formation of higher-order structures from actin filaments and in the regulation of actin dynamics in eukaryotic cells. It belongs to the Villin/gelsolin/fragmin superfamily of actin binding proteins and is composed of six gelsolin-homology domains at its core and a Villin headpiece domain at its C terminus. Recently, several Villin family members from plants have been shown to sever, cap, and bundle actin filaments in vitro. Here, we characterized a Villin isovariant, Arabidopsis thaliana Villin5 (VLN5), that is highly and preferentially expressed in pollen. VLN5 loss-of-function retarded pollen tube growth and sensitized actin filaments in pollen grains and tubes to latrunculin B. In vitro biochemical analyses revealed that VLN5 is a typical member of the Villin family and retains a full suite of activities, including barbed-end capping, filament bundling, and calcium-dependent severing. The severing activity was confirmed with time-lapse evanescent wave microscopy of individual actin filaments in vitro. We propose that VLN5 is a major regulator of actin filament stability and turnover that functions in concert with oscillatory calcium gradients in pollen and therefore plays an integral role in pollen germination and tube growth.
