Local and Physiological Control of Germline Stem Cell Lineages in Drosophila melanogaster

Abstract

The long-term survival of any multicellular species depends on the success of its germline in producing high-quality gametes and maximizing survival of the offspring. Studies in Drosophila melanogaster have led our growing understanding of how germline stem cell (GSC) lineages maintain their function and adjust their behavior according to varying environmental and/or physiological conditions. This review compares and contrasts the local regulation of GSCs by their specialized microenvironments, or niches; discusses how diet and diet-dependent factors, mating, and microorganisms modulate GSCs and their developing progeny; and briefly describes the tie between physiology and development during the larval phase of the germline cycle. Finally, it concludes with broad comparisons with other organisms and some future directions for further investigation.

Coordinating Proliferation, Polarity, and Cell Fate in the Drosophila Female Germline

“…In Drosophila, oogenesis is maintained in adult females by the proliferative activity of GSCs. Loss of GSCs, either by experimental ablation, genetic mutation, decreased nutrition, or female aging, blocks oocyte production (reviewed in Drummond- Barbosa, 2019;Kahney et al, 2019). GSCs must maintain an undifferentiated state while also continuing to proliferate.…”

“…In the anterior germarium, somatic cells form two paracrine signaling centers that collectively promote GSC self-renewal and germ cell differentiation (Figure 6). The anterior "stem cell niche" is formed by terminal filament cells and cap cells at the tip of each germarium ( Figure 2D) (Xie, 2013;Drummond-Barbosa, 2019). GSCs are physically anchored to cap cells via adherens junctions and gap junctions, which are required for maintaining GSCs in the niche (Song et al, 2002;Gilboa et al, 2003).…”

“…In the anterior half of the germarium, cysts arise from the mitotic expansion of GSCs and their differentiating daughters (Figures 2D, 3). GSCs divide mitotically with asymmetric division, giving rise to two cells of unequal fates: a new stem cell and a cystoblast destined for differentiation (Schüpbach et al, 1978;Wieschaus and Szabad, 1979;Lin and Spradling, 1993;reviewed in: Xie, 2013;Gleason et al, 2018;Drummond-Barbosa, 2019;Kahney et al, 2019). The cystoblast undergoes exactly four rounds of mitotic division with incomplete cytokinesis, creating interconnected 2, 4, 8, and 16 cell cysts (King, 1970;Spradling, 1993).…”

Neuronal octopamine signaling regulates mating-induced germline stem cell increase in female Drosophila melanogaster

“…The ovaries of the fruit fly Drosophila melanogaster are an excellent model system on how stem cell lineages are shaped by both local niche signals and tissue-extrinsic signals ( Drummond-Barbosa, 2019 ). D. melanogaster ovary is composed of 16–20 chains of developing egg chambers called ovarioles.…”

Drosophila p53isoforms have overlapping and distinct functions in germline genome integrity and oocyte quality control

“…The germline cells are surrounded by an epithelial sheet of somatic follicle cells that divide mitotically up until stage 6, and then undergo three endocycles from stages 7-10 ( Calvi et al 1998;Deng et al 2001;Jia et al 2015). Both germline and somatic follicle cell progenitors are continuously produced by germline and somatic stem cells that reside in a structure at the tip of the ovariole known as the germarium (King 1970;Drummond-Barbosa 2019).…”