title: The POF1B candidate gene for premature ovarian failure regulates epithelial polarity.
abstract: POF1B is a candidate gene for premature ovarian failure (POF); it is mainly expressed in polarised epithelial tissues, but its function in these tissues and the relationship with the disorder are unknown. Here we show colocalisation of POF1B with markers of both adherens and tight junctions in human jejunum. The tight junction localisation was maintained by the human POF1B stably expressed in the MDCK polarised epithelial cell line, whereas it was lost by the POF1B R329Q variant associated with POF. Localisation of apico-basal polarity markers and ultrastructure of the tight junctions were maintained in cells expressing the mutant. However, tight junction assembly was altered, cells were dysmorphic and the monolayer organisation was also altered in three-dimensional culture systems. Moreover, cells expressing the POF1B R329Q variant showed defects in ciliogenesis and cystogenesis as a result of misorientation of primary cilia and mitotic division. All of these defects were explained by interference of the mutant with the content and organisation of F-actin at the junctions. A role for POF1B in the regulation of the actin cytoskeleton was further verified by shRNA silencing of the endogenous protein in human intestinal Caco-2 cells. Taken together, these data indicate that localisation of POF1B to tight junctions has a key role in the organisation of epithelial monolayers by regulating the actin cytoskeleton.
authors.affiliation: Department of Pharmacology, Medical School, Università degli Studi di Milano, 20129 Milan, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Padovano
authors.forename: Ilaria
authors.initials: I
authors.lastname: Lucibello
authors.forename: Valentina
authors.initials: V
authors.lastname: Alari
authors.forename: Pamela
authors.initials: P
authors.lastname: Della Mina
authors.forename: Arianna
authors.initials: A
authors.lastname: Crespi
authors.forename: Ilaria
authors.initials: I
authors.lastname: Ferrari
authors.forename: Marta
authors.initials: M
authors.lastname: Recagni
authors.forename: Donatella
authors.initials: D
authors.lastname: Lattuada
authors.forename: Marco
authors.initials: M
authors.lastname: Righi
authors.forename: Daniela
authors.initials: D
authors.lastname: Toniolo
authors.forename: Antonello
authors.initials: A
authors.lastname: Villa
authors.forename: Grazia
authors.initials: G
authors.lastname: Pietrini
mesh_terms: D000199:Actins / Q000378:metabolism; D019943:Amino Acid Substitution; D000818:Animals; D018938:Caco-2 Cells; D016764:Cell Polarity / Q000235:genetics*; D048430:Cell Shape; D002923:Cilia / Q000502:physiology; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism / Q000502:physiology*; D005260:Female; D055785:Gene Knockdown Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007583:Jejunum / Q000166:cytology; D008840:Microfilament Proteins; D008856:Microscopy, Fluorescence; D016649:Primary Ovarian Insufficiency / Q000235:genetics*; D021381:Protein Transport; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D019108:Tight Junctions / Q000378:metabolism
chemical_list: D000199:Actins; D008840:Microfilament Proteins; C500687:POF1B protein, human; D011506:Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins