Upright Imaging of <em>Drosophila</em> Egg Chambers

Abstract

Drosophila melanogaster oogenesis provides an ideal context for studying varied developmental processes since the ovary is relatively simple in architecture, is well-characterized, and is amenable to genetic analysis. Each egg chamber consists of germ-line cells surrounded by a single epithelial layer of somatic follicle cells. Subsets of follicle cells undergo differentiation during specific stages to become several different cell types. Standard techniques primarily allow for a lateral view of egg chambers, and therefore a limited view of follicle cell organization and identity. The upright imaging protocol describes a mounting technique that enables a novel, vertical view of egg chambers with a standard confocal microscope. Samples are first mounted between two layers of glycerin jelly in a lateral (horizontal) position on a glass microscope slide. The jelly with encased egg chambers is then cut into blocks, transferred to a coverslip, and flipped to position egg chambers upright. Mounted egg chambers can be imaged on either an upright or an inverted confocal microscope. This technique enables the study of follicle cell specification, organization, molecular markers, and egg development with new detail and from a new perspective. Video LinkThe video component of this article can be found at

Tissue landscape alters adjacent cell fates during Drosophila egg development

“…To observe the pattern of border cell specification at the anterior, we developed a method to observe egg chambers end-on 24 . We first used the genotype slbo-Gal4, UAS-mCD8-GFP (referred to here as the slbo reporter 25 , 26 , Fig.…”

“…1a ) to mark the border cells, which reveals the Slbo expression gradient across the anterior epithelium. We manually sorted and mounted individual egg chambers in glycerin jelly standing with the anterior end facing up 24 , 27 ( Fig. 1b ).…”

“…Upright imaging method is described in detail in 24 . Briefly, melted glycerin jelly was spread over microscope slides and chilled overnight.…”

“…1a,b ). To investigate whether this landscape of neighboring tissue influences morphogen-mediated cell fate decisions in the follicular epithelium, we developed a new strategy to view egg chambers 24 . This protocol positions the polar cells above the nurse cells, providing a unique perspective.…”