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Fig. 2 Ziwi Is Necessary for the Maintenance of the Germline
(A) Overview of Ziwi with PAZ and PIWI domain is shown. DDH motif is indicated by arrowheads. Three STOP mutations—Q543STOP (hu2479), R561STOP (fh219), and Y728STOP (fh221)—and two missense mutations—N686K (hu2410) and I694N (fh222)—are located in the PIWI domain of ziwi.
(B) Hematoxylin and eosin staining of wild-type (left), ziwi(Q543STOP/N686K) (middle), and ziwi(Q543STOP) (right) testis is shown. Ziwi(Q543STOP/N686K) testis show fewer germ cells with almost no sperm. Ziwi(Q543STOP) mutants have germ cell-depleted testis.
(C) Caspase-3 staining (brown) shows apoptotic cells, indicated by arrows. In wild-type testis very few apoptotic cells are observed. Heterozygous ziwi(Q543STOP/+) testis show several apoptotic cells, but overall morphology is wild-type. Ziwi(Q543STOP/N686K) transheterozygous mutants have few, if any, sperm cells, and many germ cells are apoptotic.
(D) Whole mount in situ hybridization of wild-type and ziwi(R561STOP/Y728STOP) gonads at 20 dpf, with staining for vasa, is shown. Loss of Ziwi leads to a strong reduction in the amount of vasa positive cells.
(E) Caspase-3 staining of wild-type and ziwi(hu2479/hu2479) animals at 21 days of development is shown. The developing germline is indicated. Wild-type gonads (n = 3) do not show apoptosis at this point in time, whereas the mutant gonads (n = 3; brown cells) do.
Reprinted from Cell, 129(1), Houwing, S., Kamminga, L.M., Berezikov, E., Cronembold, D., Girard, A., van den Elst, H., Filippov, D.V., Blaser, H., Raz, E., Moens, C.B., Plasterk, R.H., Hannon, G.J., Draper, B.W., and Ketting, R.F., A role for Piwi and piRNAs in germ cell maintenance and transposon silencing in Zebrafish, 69-82, Copyright (2007) with permission from Elsevier. Full text @ Cell