part of develops_from prestalk A region of the standing slug prestalk region of the early culminant prestalk O region of the early culminant Area of the prestalk zone of the early culminant located posterior to the pstA region and characterized by low expression of the ecmA gene directed by the distal part of its promoter (ecmO promoter). DDANAT:0000039 Dictyostelium_discoideum_anatomy pstO region of the early culminant prestalk O region