By contrast, both RVCL and ΔExo RVCL TREX1 mutants were localized throughout the cell, including a much larger fraction in the nucleus (Fig. 1c, d), which suggests that nuclear localization of enzymatically active TREX1 exacerbates eye disease in Drosophila. The disease phenotype in Drosophila expressing WT TREX1 might be explained by over-expression, which might drive a certain amount of nuclear mislocalization of full-length TREX1. The gene discussed is TREX1; the disease is eye disorder.