Automatic stage identification of Drosophila egg chamber based on DAPI images

Abstract

The Drosophila egg chamber, whose development is divided into 14 stages, is a well-established model for developmental biology. However, visual stage determination can be a tedious, subjective and time-consuming task prone to errors. Our study presents an objective, reliable and repeatable automated method for quantifying cell features and classifying egg chamber stages based on DAPI images. The proposed approach is composed of two steps: 1) a feature extraction step and 2) a statistical modeling step. The egg chamber features used are egg chamber size, oocyte size, egg chamber ratio and distribution of follicle cells. Methods for determining the on-site of the polytene stage and centripetal migration are also discussed. The statistical model uses linear and ordinal regression to explore the stage-feature relationships and classify egg chamber stages. Combined with machine learning, our method has great potential to enable discovery of hidden developmental mechanisms.

Tissue tension and not interphase cell shape determines cell division orientation in the Drosophila follicular epithelium

“…While an earlier study failed to detect a bias in the orientation of planar cell divisions, developmental stage was not accounted for in that work (Alégot et al, 2018). We determined egg chamber stage by calculating volume, with adjustments based on nuclear staining pattern, and by defining the switch between 6 and 7 as the cessation of follicle cell mitoses (Klusza & Deng, 2011;Jia et al 2016;Ng et al, 2016). We next considered whether the bias in division orientation is driven by egg chamber shape change.…”

“…We tested this possibility by disrupting Fat2 (previously Kugelei), which is required for egg chamber rotation (Viktorinová et al, 2009;Cetera et al, 2014). We determined egg chamber stage by calculating volume, with adjustments based on nuclear staining pattern, and by defining the switch between 6 and 7 as the cessation of follicle cell mitoses (Klusza & Deng, 2011;Jia et al 2016;Ng et al, 2016). Using this method, we found that Fat2-shRNA egg chambers are modestly, but significantly, less elongated than wild-type egg chambers at stage 6 (Figs 4C and EV2G and H).…”

Dynamic and Stable Cohesins Regulate Synaptonemal Complex Assembly and Chromosome Segregation

“…A) Schematic showing the timeline of oocyte development [48, 49]. B) Nondisjunction in c(2)M − ; UASp-c(2)M 3XHA /hs-Gal4 females measured following 1 hour of heat shock and the number of days indicated within each bar.…”

Endocrine network essential for reproductive success in Drosophila melanogaster

“…Samples were washed 5× and TUNEL-stained using the Roche In Situ Cell Death Detection Kit, TMR Red according to the manufacturer's protocol. Egg staging was performed as described by Wijesekera et al (56). Ovaries of virgin day 5 females of indicated genotype were raised individually in isolation vials, dissected in PBS, and 10 mature, stage 14 oocytes were collected from 10 sample flies.…”