Males expressing eIF-4E^HMS00969 under Scer\GAL4^{nos.UTR.T:Hsim\VP16} control are sterile. Their testes are considerably smaller than wild-type, and they do not produce differentiated cell types characteristic of the different stages of spermatogenesis. Instead, the apical tip of the testes contains a mass of cells that do not organise into germ cell cysts, while the rest of the structure consists of a lumen that is devoid of germ cells. Spermatocytes and spermatids are absent - testes show a chromosome condensation state that is characteristic of spermatogonial cells. Thus germ line development is blocked during or before the transit-amplifying divisions. The epithelium surrounding the apical cell mass appears disorganized and multi-layered.

Males expressing eIF-4E^HMS00969 in cyst cells (under Scer\GAL4^C587 control) are sterile and produce only rudimentary testes which appear smaller and disorganized.

Males expressing eIF-4E^HMS00969 under Scer\GAL4^{bam.T:Hsim\VP16} control does not affect gross development or morphology of germ cells in primary spermatocyte to elongating spermatid stages. However, needle-like nuclear bundles at the rostral end of the elongated spermatids and not detected, and instead the nuclei rae round and distributed along the entire length of the flagellar axoneme cysts. Thus nuclear condensation and individualization has failed. The progression of mitotic and meiotic cell divisions in primary spermatocytes is normal in these mutants. Scer\GAL4^{bam.T:Hsim\VP16} eIF-4E^HMS00969 testes show defective organization of spermatid bundles, and while spermatid cysts complete elongation and initiate individualization, the elongated spermatids are consistently shorter than wild type. During the meiotic stages, chromosome condensation and segregation is defective: M4 stage spermatocytes frequently have multiple nuclei, each containing dispersed chromatin structures, and the flagellar axonemes fail to complete individualization. Mitochondrial compaction and differentiation are unaffected.

Leaky expression of eIF-4E^HMS00969 (in the absence of a GAL4) significantly increases the number of extra satellite boutons seen at the neuromuscular junction in third instar larvae; expression driven by Scer\GAL4^elav-C155 significantly increases the number of satellite boutons (compared to eIF-4E^HMS00969 alone).