Fig. 4. slam is encoded by CG9506 and is expressed in blastoderm embryos. (A) Male mitotic recombination mapping placed slam between k13720 and k07502, a region with 16 predicted genes. (B) Genomic structure of CG9506. Boxes represent exons. Sequencing of the slam^waldo alleles revealed a nonsense mutation at Q722 in slam^waldo1 and a glycine to lysine change at G879 in slam^waldo2. (C) slam RNA expression in a stage 2 embryo. There is no zygotic transcription at this stage, thus the weak expression in early embryos is maternal RNA contribution. (D) Stage 4. There are high amounts of slam in somatic nuclei, but not in germ cells, where zygotic transcription is repressed (inset). (E) Stage 6 embryo. By the end of cellularization, slam decays to three stripes in the blastoderm. (F) Stage 11 embryo. By the end of gastrulation, slam is no longer expressed.