Deficiency breakpoint within the asun locus.
centrosome, with bor+t4
spermatid (with asunf02815), with bor+t4
Homozygous asund93 females have a severely reduced egg-laying rate (less than 1 egg/day per female compared to 55 eggs/day per wild-type control female). Heterozygous females have a normal egg-laying rate.
The parovaria, spermathecae and seminal receptacles of homozygous females appear morphologically normal.
The ovaries of homozygous 2 day old females are considerably smaller than normal. The mutant ovarioles typically contain early and late-stage egg chambers with a paucity of intermediate stages.
20% of stage 10 homozygous egg chambers contain an increased number of germ cells, possibly due to a fusion of two or more egg chambers. Disruption of the follicle cell border that normally demarcates nurse cells and the oocyte is seen in 10% of homozygous egg chambers at or beyond stage 10.
54% of eggs laid by asund93 females have dorsal appendage defects, with 23% completely lacking dorsal appendages. 6% of eggs laid by asund93 females lack a micropyle.
Oocyte nucleus-centrosome coupling defects are seen in 18% of asund93 egg chambers. Oocyte nuclei of mutant and wild-type stage 9 egg chambers are similarly positioned, but by stage 10, only 67% of mutant egg chambers show the normal anterior-dorsal positioning of the oocyte nucleus.
Fusome structure appears normal in asund93 germaria. However, there are defects in centrosome migration: centrosomes are still distributed throughout the cyst in 67% of stage 3 mutant germaria (in wild type they have migrated to the oocyte by this stage) and 42% of mutant stage 5 egg chambers have a decreased number of centrosomes associated with the oocyte nucleus than normal.
asund93 mutant males (expressing bor+t4 to restore bor[+] function) are sterile.
Cortical centrosomes are rarely seen in the spermatocytes of asund93 mutant flies (expressing bor+t4 to restore bor[+] function). Severe prophase I arrest occurs and the few round spermatids that are seen contain multiple nuclei and four basal bodies, indicative of severe cytokinesis defects. Nucleus-nebenkern and nucleus-basal body uncoupling are frequently seen, although nebenkern-basal body attachments are unaffected.
asund93/asunf02815 mutant spermatids (expressing bor+t4 to restore bor[+] function) display frequent nucleus-nebenkern and nucleus-basal body uncoupling. Nebenkern-basal body attachments are unaffected.
