lola encodes a family of BTB-Zf transcriptional regulators expressed in germline and somatic cells in the testis: (A) Diagram of Drosophila spermatogenesis. Green: GSC lineage. Gray: CySC lineage. Asterisks: CySCs. Black: hub. Gb: gonialblast, encysted by two cyst cells (gray). Primary spermatocytes: large germ cells with prominent nucleoli (dark dots in nuclei). For simplicity, the division products of one spermatocyte are shown. (B) Lola protein isoforms A–T (N termini at left). Gray: Common N-terminus with BTB domain. Colored: Alternately spliced C-terminal exons. White bars: zinc finger motifs. C2HC-C2H2 zinc fingers motifs: B, C, D, F, H, J, K, L, O, P, Q, R, T. C2HC-C2HC zinc finger motifs: I and N. C2H2 motif: E, S. Isoforms A, G and M do not have predicted zinc finger domains. (C) Wildtype testis stained with pan Lola antibody. Red: Lola. Green: nos-Gal4, UAS-tubulin-GFP. Blue: DAPI. Dotted outline: hub. Asterisks: GSCs. Red arrowhead: spermatogonia. Yellow arrowhead: CySC. Arrow: Cyst cell. Scale bar: 20 μm. (D) lolaORE76 mosaic testis at 2 days post clone induction stained with pan Lola antibody. Red: Lola. Green: Ubi-nls-GFP (clonal marker). Yellow outline: homozygous mutant lolaORE76 GSC. Red outline: hub. Asterisks: GSCs. Arrowheads: CySC nuclei. Arrow: spermatogonia. Scale bar: 15 μm.