piwi1/+ (or even more so, piwi1/piwi2) significantly partially suppresses the swollen apical tip of the testis phenotype seen in Tudor-SN0614/Tudor-SN1120 males. piwi1/piwi2 suppresses infertility seen in Tudor-SN0614/Tudor-SN1120 males. Tudor-SN0614/Tudor-SN1120 partially suppresses ovary defects in piwi1/piwi2 females.
piwi1/+ enhances the eye outgrowth phenotype phenotype of KrIf-1; approximately 7% of the progeny have an eye outgrowth phenotype in a cross of piwi1/+ females to KrIf-1/+ males. However, the reciprocal cross of KrIf-1/+ females to piwi1/+ males does not result in progeny with an eye outgrowth phenotype, indicating a maternal effect.
The frequency with which l(3)mbtts1 larval brain tissue develops into tumours after allograft into adult host flies (taking over the entire abdomen of the host) is markedly reduced if the transplanted tissue is also homozygous for piwi1.
The frequency with which bratk06028 larval brain tissue develops into tumours after allograft into adult host flies (taking over the entire abdomen of the host) is not significantly altered if the transplanted tissue is also homozygous for piwi1.
When piwiEP1024 is overexpressed under the control of Scer\GAL4hs.PB using heat shock treatment (1 hour at 37oC every day starting from the larval stage) in a piwiEP1024/piwi1 background, significant rescue of the piwiEP1024/piwi1 mutant phenotype is seen in both females and males. Specifically, in females, germline stem cells are maintained and a string of developing egg chambers are observed, while in males, germline stem cells are also rescued and spermatogenesis is fully restored. Fertility is rescued to wild-type levels. Heat shock starting at the pupal stage does not rescue fertility.