Lead (Pb+2) effects in global gene expression in the larval brain of Drosophila melanogaster. Drosophila melanogaster

Lead (Pb2+) is an environmental contaminant that is widely distributed around the world, mainly due to anthropogenic sources. Developmental exposure to Pb2+ has been linked to neurodevelopmental impairments in different animal species. Studies have shown that developmental exposure to Pb2+ could interfere with normal gene expression patterns in the immature brain leading to neurodevelopmental neuropathologies. However, the precise molecular mechanisms underlying the neurotoxicity of developmental Pb2+ exposure are still to be elucidated. We used the fruit fly to gain insights into the molecular mechanisms affected by exposure to this neurotoxicant. The fruit fly, has been used recently to understand the behavioral, synaptic and molecular changes after developmental exposure to Pb+2. Our overarching hypothesis is that developmental exposure of the fruit fly to Pb+2 results in global gene expression dysregulation in the larval brain resulting in central nervous system developmental impairments. We collected RNA samples from larval brain of control and Pb2+-exposed flies and performed cRNA hybridization on a 4x44K Agilent microarray. Overall, Pb+2 results in transcriptional disturbances of important developmental signaling pathways in the larval brain. Overall design: The experimental design consisted of four microarray experiments. Cy-5 labeled cRNA control targets were combined with Cy-3 labeled cRNA experimental (Pb+2) targets obtained from brains of wandering third instar larvae. The combined Cy-5 and Cy-3 cRNAs targets were used for probe hybridization onto the first and third microarray, respectively. Dye swapping was done using different biological replicates for both Cy-3 labeled control targets and the Cy-5 Pb+2 targets (as above) and used for hybridization on the second and fourth microarray respectively. Dye swaps using different biological replicates were done to correct for any dye-bias.