egg chamber (with mei-P26fs1)
mei-P26mfs1 ovaries exhibit arrest in early oogenesis.
Testes of homozygous males have cysts full of many small cells, which appear similar to early germ cells seen at the apical tip of the wild-type testis. EdU incorporation assays show that early germ cells in the mutant testis undergo several extra rounds of mitotic division and behave as transit amplifying cells rather than as stem cells, with all cells within a cyst undergoing S phase synchronously. The overproliferating cysts in the mutant testes eventually degenerate. The nucleoli of mutant early germ cells are larger than normal. 32% of germline cysts do switch to the spermatocyte state, but only a third of these contain the normal number of 16 spermatocytes per cyst and the differentiating cells show a number of gross morphological defects.
Germaria are filled with individual spectrosome-containing cells and cysts containing varying numbers of cells connected by a fusome in mutant ovaries. Nurse cells and oocytes are not formed and fusomes or spectrosomes are maintained at later stages of oogenesis.
Cell diameters are increased compared to wild type and no longer decrease as cells are displaced from the stem cell niche in mei-P26fs1/mei-P26mfs1 ovaries.
Homozygous ovaries are completely tumourous and no normal looking egg chambers are seen. Homozygous females do not lay eggs. Testes of hemizygous males do not contain any mature motile spermatozoa, although somewhat disorganised immature elongated spermatid bundles are produced. In addition, the testes contain highly refractile cysts that most likely represent degenerating cysts of spermatogonial cells.
mei-P26mfs1 has male germline cyst phenotype, suppressible | partially by bam+t2.9
mei-P26mfs1 has male germline cyst phenotype, suppressible | partially by bamΔPEST
mei-P26mfs1 has nucleolus phenotype, suppressible by bam+t2.9
mei-P26mfs1 has nucleolus phenotype, suppressible by bamΔPEST
Expression of bam+t2.9 completely rescues the overproliferation defects seen in the testes of mei-P26mfs1 males and 72% of the cysts in the spermatocyte region have 16 spermatocytes per cyst. The enlarged nucleolus phenotype seen in mei-P26mfs1 testes is also suppressed. The spermatocyte and spermatid differentiation defects are not rescued: 27% of cysts from the spermatocyte region have differentiation defects in the rescued males.
Expression of bamΔPEST completely rescues the overproliferation defects seen in the testes of mei-P26mfs1 males and 43% of the cysts in the spermatocyte region have 16 spermatocytes per cyst. The enlarged nucleolus phenotype seen in mei-P26mfs1 testes is also suppressed. The spermatocyte and spermatid differentiation defects are not rescued: 30% of cysts from the spermatocyte region have differentiation defects in the rescued males.
mei-P26mfs1 is rescued by mei-P26+t13
mei-P26mfs1 is rescued by mei-P26+t13
The overproliferating spermatogonial cysts and spermatocyte differentiation defects seen in the testes of mei-P26mfs1 males are rescued by Dp(1;4)A17 and by mei-P26+t13.