Fig. 4. Cell-type-specific expression of BC1 RNA in seminiferous tubules. In situ hybridization was performed with testes from homozygous (W^V/W) germ-line deficient mutant mice (C,D), and with testes from wild-type (+/+) littermates (A,B). Little specific signal is observed in seminiferous tubules of germ-line-deficient animals. Note that most of the brightness associated with cells in C is not caused by silver grains but by reflections from cellular structures. (A,C) Dark field photomicrographs; (B,D) bright field photomicrographs. Bar, 100 µm. (E) Northern hybridization with 10 µg total RNA isolated from germ-line-deficient adult testes (lane 1) or wild-type adult testes (lane 2). BC1 RNA is not detected in germ-line-deficient testes. Equal loading was verified as described in Materials and Methods. (F) Northern hybridization with RNA isolated from enriched populations of spermatogenic cells. Lane 1, total RNA from entire adult testis (total RNA loaded in this and other lanes: 15µg); lane 2, poly(A)⁺ RNA from entire testis (5 µg); lane 3, poly(A)^- RNA from entire testis (25 µg); lane 4, total RNA from cells in the prophase of meiosis (mainly pachytene); lane 5, total RNA from early spermatids; lane 6, total RNA from the fraction containing cytoplasmic fragments of elongating speriment and residual bodies. For the experiment shown in F, a filter used for a previous publication [(Zakeri et al., 1988) see figure 5, third panel)] was reprobed with BC1-specific probe HT005. Arrows in E and F indicate the position of the BC1 RNA band on the two blots.