title: Vacuole dynamics in the salivary glands of Drosophila melanogaster during prepupal development.
abstract: A central function of the Drosophila salivary glands (SGs), historically known for their polytene chromosomes, is to produce and then release during pupariation the secretory glue used to affix a newly formed puparium to a substrate. This essential event in the life history of Drosophila is regulated by the steroid hormone ecdysone in the late-larval period. Ecdysone triggers a cascade of sequential gene activation that leads to glue secretion and initiates the developmentally-regulated programmed cell death (PCD) of the larval salivary glands, which culminates 16 h after puparium formation (APF). We demonstrate here that, even after the larval salivary glands have completed what is perceived to be one of their major biological functions--glue secretion during pupariation--they remain dynamic and physiologically active up until the execution phase of PCD. We have used specific metabolic inhibitors and genetic tools, including mutations or transgenes for shi, Rab5, Rab11, vha55, vha68-2, vha36-1, syx1A, syx4, and Vps35 to characterize the dramatic series of cellular changes occurring in the SG cells between pupariation and 7-8 h APF. Early in the prepupal period, they are remarkably active in endocytosis, forming acidic vacuoles. Midway through the prepupal period, there is abundant late endosomal trafficking and vacuole growth, which is followed later by vacuole neutralization and disappearance via membrane consolidation. This work provides new insights into the function of Drosophila SGs during the early- to mid-prepupal period.
authors.affiliation: Laboratory of Developmental Genetics, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlárska 3, 83306, Bratislava, Slovakia.
authors.forename: Robert
authors.initials: R
authors.lastname: Farkaš
authors.forename: Denisa
authors.initials: D
authors.lastname: Beňová-Liszeková
authors.forename: Lucia
authors.initials: L
authors.lastname: Mentelová
authors.forename: Silvia
authors.initials: S
authors.lastname: Mahmood
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Ďatková
authors.forename: Milan
authors.initials: M
authors.lastname: Beňo
authors.forename: Ludmila
authors.initials: L
authors.lastname: Pečeňová
authors.forename: Otakar
authors.initials: O
authors.lastname: Raška
authors.forename: Jana
authors.initials: J
authors.lastname: Šmigová
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Chase
authors.forename: Ivan
authors.initials: I
authors.lastname: Raška
authors.forename: Bernard M
authors.initials: BM
authors.lastname: Mechler
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster; D004440:Ecdysone / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000235:genetics / Q000378:metabolism*; D011679:Pupa; D012469:Salivary Glands / Q000166:cytology / Q000378:metabolism*; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D004440:Ecdysone
keywords: endosomal trafficking; metamorphosis; prepupal period; salivary glands; vacuolation