Figure 1

Strategy for enrichment of transcripts expressed in the yolk syncytial layer. (1A) schematic of strategy. Embryos were injected with purified Kaede protein after fertilization, labelling all cells green, and incubated until the blastula stage (5 hpf - "pre-gastrula embryos" in schematic), then either directly harvested for mRNA extraction and probe generation, or FACS sorted followed by mRNA extraction and probe generation. Differentially labeled probes from these two procedures were co-hybridized onto microarrays. The exclusion of yolk globules was observed in microscopic examinations of post-FACS samples (data not shown), and the exclusion of YSL nuclei and EVL is inferred from subsequent analyses described in this paper. (1B) volcano plot representation of microarray hybridization. A substantial number of genes with significantly elevated transcript levels are apparent, both in the whole embryo (537 oligos outlined by the blue box which correspond to 359 unique genes) and embryonic cell cohorts (1697 oligos which correspond to 1210 unique genes, using analogous criteria, see Methods).