RNA-Seq gene expression regulated by Drosophila insulin-like peptides DILP2 and DILP5 in S2 cells

Mammalian insulin and IGF induce similar but not identical changes in gene expression downstream of their respective receptors. Signaling bias at the receptor differentiates the two similar ligands, though the precise mechanism is not entirely understood. We used Drosophila insulin-like peptides DILP2 and DILP5 to determine how similar insulin-like ligands regulate similar and distinct patterns of gene expression in S2 cells by RNA-Seq. Overall, DILP2 and DILP5 stimulate many of the same changes in gene expression. However, some genes are uniquely regulated by DILP2 or by DILP5. Shared and distinct gene targets were validated by q-RT-PCR with indepedent replicates. Some unique gene targets of DILP2 are involved in sugar metabolism, which is functionally related in vivo to DILP2 and not DILP5. We find that gene expression is largely regulated in parallel by DILP2 and DILP5 but some key unique targets may lead to differential physiological functions for the two insulin-like genes. mRNA profiles from S2 cells treated with DILP2, DILP5 or solvent were sequenced on an Illumina HiSeq2500