Fig. 3. tomb expression is primary spermatocyte-specific. (A) RT-PCR of tomb ORF from female bodies lacking ovaries (fb), ovaries (ov), male bodies lacking testes (mb), testes (te) and 0-16 hour embryos (em). Negative control (-ve) was without reverse transcriptase. Positive control (+ve) was gDNA. (B) Semi-quantitative RT-PCR on testis RNA showed just detectable levels of transcript in wild type (WT), and slightly elevated levels in the meiotic-arrest mutants aly and mia. Controls as in A. (C,D) RNA in situ hybridisation. (C) In wild type, tomb expression was exclusively detected in primary spermatocytes. Early primary spermatocytes showed robust staining (arrow); mRNA levels gradually declined as spermatocytes matured (arrowhead). (D) tomb mRNA expression levels in aly mutant early primary spermatocytes was similar to wild type (arrow); however, levels did not decline as spermatocytes matured (arrowhead).