The emergence of sense organs in the wing disc of <i>Drosophila</i>

TLDR

Mechanosensory organ types are indistinguishable until the late larval stage. The study aims to chart the timing and division pattern of sensory mother cells that generate the notum’s macro‑chaetes, trichoid sensilla, and the wing’s campaniform sensilla. We observed that the sensory mother cells appear in a strict sequence during the late third instar and the first 10 h of pupation, with a lag of 30 h to 2 h between lacZ activation and the first division and with cell‑specific orientation of that division.

Abstract

ABSTRACT We have examined the origin of a set of precisely located sense organs in the notum and wing of Drosophila, in transformant flies where lacZ is expressed in the progenitor cells of the sense organs (the sensory mother cells) and in their progeny. Here we describe the temporal pattern of appearance and divisions of the sensory mother cells that will form the eleven macro-chaetes and the two trichoid sensilla of the notum, and five campaniform sensilla on the wing blade. The complete pattern of sensory mother cells develops in a strict sequence that extends over most of the third larval instar and the first 10 h after puparium formation. The delay between the onset of lacZ expression and the first differentiative division ranges from 30 h, in the case of the earliest mother cells, to 2 h for the latest mother cells. The first division shows a preferential orientation which is also specific for each sensory mother cell. Up to this stage, there is no marked difference between the three types of mechanosensory organs.