title: Expression of the neurosecretory process in PC12 cells is governed by REST.
abstract: The neurosecretory process is acquired during differentiation and can be lost en block by differentiated cells. To investigate the role of REST/NRSF, a transcription repressor, in the maintenance of the process we studied two PC12 clones, one wt and one defective, expressing low and high levels of endogenous RE-1 silencing transcription (factor) (REST), respectively. Stable transfection of constructs demonstrated that REST represses 10 genes coding for proteins of neurosecretory vesicles and their exocytosis, eight including and two lacking the REST-binding sequence, RE-1. Of these genes, those of chromogranins were strongly repressed by fewfold increases of REST, those of VAMP2 and syntaxin1a required much higher levels. Moreover, in wt cells transfected with an active construct the dense-core vesicles, still competent for regulated exocytosis, were much smaller, with lighter cores; in defective cells, the dominant-negative construct induced the rescue of many vesicle/exocytosis genes but not of those of chromogranins. Small dense-core vesicles, exocytized upon stimulation, were rescued when the construct-transfected defective cells were transfected also with chromograninA or treated with trichostatinA, a blocker of histone deacetylases. Our results identify REST, working by direct and indirect mechanisms, as the factor governing the maintenance of the neurosecretory process and the properties of dense-core vesicles in PC12 cells.
authors.affiliation: Vita-Salute San Raffaele University, Center of Excellence in Cell Development, Milan, Italy.
authors.forename: Rosalba
authors.initials: R
authors.lastname: D'Alessandro
authors.forename: Andrijana
authors.initials: A
authors.lastname: Klajn
authors.forename: Laura
authors.initials: L
authors.lastname: Stucchi
authors.forename: Paola
authors.initials: P
authors.lastname: Podini
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Malosio
authors.forename: Jacopo
authors.initials: J
authors.lastname: Meldolesi
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology*; D009489:Neurosecretion / Q000502:physiology*; D016716:PC12 Cells; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D000099229:RE1-Silencing Transcription Factor
chemical_list: D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D000099229:RE1-Silencing Transcription Factor