A gelatinous mass assembled by the fusion of the adjacent fusomes (q.v.) formed at consecutive cystocyte divisions in Drosophila. The diagram illustrates a polyfusome in a cystocyte clone during the divison of 8 cells into 16. Cell 1 is obscured by the cells lying above it. In each of the other seven cells, a spindle and a ring canal (q.v.) can be seen. Pairs of centrioles lie at the spindle poles. The polyfusome protrudes through each ring canal and touches one pole of each spindle. As a result of this orientation, one cell of each dividing pair will retain all previously formed ring canals, while the other will receive none. These spindle-fusome alignments during the cycle of cystocyte divisions (q.v.) produce a branched chain of interconnected cells. There are always two central cells, each with four ring canals. In female sterile mutations characterized by ovarian tumors, polyfusomes often fail to form properly, and the pattern of germ cell divisions and their differentiation are abnormal. See bag of marbles (bam), fusome, hu-li tai shao (hts), otu, pro-oocyte.
From P. D. Storto and R. C. King, 1989, The role of polyfusomes in generating branched chains of cystocytes during Drosophila oogenesis. Dev. Genet. 10: 70–86, Fig. 8. © 1989 by John Wiley & Sons, Inc. Reprinted with permission of Wiley-Liss, Inc., a subsidiary of John Wiley & Sons, Inc.
Subjects: Genetics and Genomics.