Identification of genes whose expression is affected by Delta RNAi in spider embryos. Identification of genes whose expression is affected by Delta RNAi in spider embryos

In the spider Parasteatoda tepidariorum embryo, Delta-Notch signaling plays a key role in early development of the opisthosomal region by regulating the balance between the caudal ectoderm and mesoderm fates (Oda et al., 2007, Development 134, 2195-2205). In this microarray experiment, we attempted to identify candidate genes whose expressions are regulated by Delta-Notch signaling during early phases of the caudal development. Overall design: The objective of this experiment was a screen for genes whose expressions might be affected by parental RNA interference (pRNAi) against Pt-Delta in spider embryos. Oligonucleotide probes were designed based on accumulated P. tepidariorum EST and cDNA sequences and embedded in a custom microarray (12K). Total RNA was extracted from late stage 5 embryos derived from a mated female before and after injection of dsRNA targeted for Pt-Delta. Gene expression levels were compared between the untreated (normal) and the Pt-Delta pRNAi-treated samples. Probes for a homolog of Drosophila caudal, Pt-cad (GB_ACC: AB096075.1; GI: LOC107437910), served as positive controls to validate this experiment.