Testes with increased EGF signaling contained few spermatogonia.

<p>(A) A wildtype testis showing co-expression of Vasa (green) and Bam (red) in many germline cells in the apical region. (A′) Same testis as in (A) showing Bam expression only. B) A wildtype testis labeled with antibodies against α-spectrin. Arrowhead: GSC containing a round fusome, small arrows: narrow fusomes interconnecting spermatogonia, large arrow: wide fusomes interconnecting spermatocytes. (C) A cyst cell-sSpi/EGFR-testis showing co-expression of Vasa (green) and Bam (red) in only a few germline cells. (C′) Same testis as in (C) showing Bam expression only. (D) A cyst cell-sSpi/EGFR-testis showing the presence of only few narrow fusomes (arrows), and the presence of GSCs with a round fusome (arrowhead), and spermatocytes with wide fusomes (large arrow). (E) Bar graph showing the differences in numbers of narrow branched fusomes between testes from control and experimental animals. Three asterisks mark a statistically significant difference compared to the control. Genotypes and stainings as indicated, asterisks in (A-D): apical tips of the testes, scale bars: 30 µm.