Bridging the divide

Abstract

Ring canals are made from arrested cleavage furrows, and provide direct cytoplasmic connections among sibling cells. They are well documented for their participation in Drosophila oogenesis, but little is known about their role in several somatic tissues in which they are also found. Using a variety of genetic tools in live and fixed tissue, we recently demonstrated that rapid intercellular exchange occurs through somatic ring canals by diffusion, and presented evidence that ring canals permit equilibration of protein among transcriptionally mosaic cells. We also used a novel combination of markers to evaluate the extent of protein movement within and across mitotic clones in follicle cells and imaginal discs, providing evidence of robust movement of GFP between the 2 sides of mitotic clones and frequently into non-recombined cells. These data suggest that, depending on the experimental setup and proteins of interest, inter-clonal diffusion of protein may alter the interpretation of clonal data in follicle cells. Here, we discuss these results and provide additional insight into the impact of ring canals in Drosophila somatic tissues.

Identification of Novel Regulators of the JAK/STAT Signaling Pathway that Control Border Cell Migration in theDrosophilaOvary

“…The ovary is composed of strings of ovarioles, and each string is composed of egg chambers at different developmental stages ( Bate and Martinez Arias 1993 ; Montell 2003 ). Each egg chamber contains 15 large nurse cells and an oocyte, which are enveloped by a layer of about 1000 follicle cells ( McLean and Cooley 2014 ). Early in oogenesis, a pair of follicle cells at the anterior and posterior ends of the egg chamber becomes differentiated into “polar cells”.…”

Methods for studying oogenesis

“…Similarly, wild-type gene product may (or may not, depending on its ability to diffuse) move from a genetically wild-type cell to a homozygous mutant cell. The extent to which this is a concern in clonal analysis of follicle cells depends on the ability of the marker and the wild-type gene product to diffuse (for a more complete discussion of these issues, see [21]).…”

“…Like the germline cysts, the follicle cells are also syncytial, as they remain interconnected with a number of sibling cells by small (~200 nm diameter) ring canals that result from incomplete cytokinesis [17–19]. These ring canals do not grow in size during oogenesis, but they are able to support intercellular movement of protein between cells, raising the interesting possibility that they serve an important function in oogenesis [20,21]. …”

Clonal dominance in excitable cell networks

“…1b , c ; Extended Data Fig. 1 ) [ 18 – 20 ]. Ring canals therefore encode the history of cell divisions, forming lineage trees of connected cells, henceforth clusters, which tile the epithelium like a jigsaw puzzle ( Fig.…”

“…1c ). By tracing ring canal connections [ 18 – 20 ], one can reconstruct the distribution of cluster sizes and their joint growth dynamics [ 21 ].…”