Evaluation of sub-cellular distribution of glutamate dehydrogenase (GDH) in Drosophila melanogaster larvae

Glutamate dehydrogenase (GDH) enzyme was conventionally known as a mitochondrial marker. However, subsequently it was reported to be present in the nuclei as well. So far, the nuclear distribution of GDH has been reported in a number of organisms including yeast, rat, cow, chicken. However, the sub-cellular distribution of GDH, illustrated by in situ methods still remains elusive. Here, by assaying the GDH activity and by immuno-blotting using anti-GDH antibody in the fractionated nuclear and cytoplasmic fractions of Drosophila larvae, we demonstrate the cytoplasmic distribution of GDH. This observation was further supported by in situ immunostaining of salivary gland, Malpighian tubules and eye imaginal discs of Drosophila larvae. Collectively, our results demonstrate that in Drosophila larvae, GDH is not found in the nucleus, but is localized exclusively in the cytoplasm.