The voltage-dependent anion channels (VDACs) are the most abundant protein found in the outer mitochondrial membrane and comprises the permeability transition pore. The involvement of VDACs in a dysfunction of the mitochondria and apoptosis is well known. Recently, a dysregulation of VDACs expression in patients with Down syndrome and Alzheimer's disease have been reported. However, the mechanism by which the VDAC gene expression is regulated is unclear. In order to examine the expression of the porin gene encoding Drosophila VDAC, this study established transgenic flies bearing the porin-lacZ fusion gene in which the promoter region (-2369 to +153 with respect to the transcription initiation site) was fused to the reporter lacZ. The porin mRNA levels, which were examined by RT-PCR, and the porin-lacZ expression levels in transgenic flies indicated that the porin gene is expressed throughout development, with higher levels at the embryonic and adult stages. Porin-lacZ expression in the third instar larvae was detected in the gut, brain, ganglion, imaginal discs, salivary gland, imaginal tracheoblasts and fat bodies. In adults, porin-lacZ expression was detected in the gut, muscles, oenocytes and reproductive systems of males and females. In addition, porin-lacZ expression was upregulated by oxidative stress in the fat body. Transgenic flies beating the porin-lacZ fusion gene might to be useful for further investigations on the regulatory mechanisins of the porin gene.