title: Spatial and temporal expression of actin depolymerizing factors ADF7 and ADF10 during male gametophyte development in Arabidopsis thaliana.
abstract: The actin cytoskeleton plays a crucial role in many aspects of plant cell development. During male gametophyte development, the actin arrays are conspicuously remodeled both during pollen maturation in the anther and after pollen hydration on the receptive stigma and pollen tube elongation. Remodeling of actin arrays results from the highly orchestrated activities of numerous actin binding proteins (ABPs). A key player in actin remodeling is the actin depolymerizing factor (ADF), which increases actin filament treadmilling rates. We prepared fluorescent protein fusions of two Arabidopsis pollen-specific ADFs, ADF7 and ADF10. We monitored the expression and subcellular localization of these proteins during male gametophyte development, pollen germination and pollen tube growth. ADF7 and ADF10 were differentially expressed with the ADF7 signal appearing in the microspore stage and that of ADF10 only during the polarized microspore stage. ADF7 was associated with the microspore nucleus and the vegetative nucleus of the mature grain during less metabolically active stages, but in germinating pollen grains and elongating pollen tubes, it was associated with the subapical actin fringe. On the other hand, ADF10 was associated with filamentous actin in the developing gametophyte, in particular with the arrays surrounding the apertures of the mature pollen grain. In the shank of elongating pollen tubes, ADF10 was associated with thick actin cables. We propose possible specific functions of these two ADFs based on their differences in expression and localization.
authors.affiliation: Université de Montréal, Département de sciences biologiques, Institut de Recherche en Biologie Végétale, 4101 Sherbrooke East, Montreal, Quebec, Canada.
authors.forename: Firas
authors.initials: F
authors.lastname: Bou Daher
authors.forename: Chloë
authors.initials: C
authors.lastname: van Oostende
authors.forename: Anja
authors.initials: A
authors.lastname: Geitmann
mesh_terms: D051339:Actin Depolymerizing Factors / Q000235:genetics / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D011058:Pollen / Q000254:growth & development*; D053205:Pollen Tube / Q000254:growth & development; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: C578064:ADF10 protein, Arabidopsis; C578063:ADF7 protein, Arabidopsis; D051339:Actin Depolymerizing Factors; D000199:Actins; D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; C485182:Cyan Fluorescent Protein; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; C054562:yellow fluorescent protein, Bacteria; D049452:Green Fluorescent Proteins