Gene expression influenced by human APE1 and mouse Ape1 in a mouse embryonic fibroblast line.

APE1 (AP-endonuclease 1) is an essential DNA repair protein but also it functions as a gene regulatory protein. A unique mouse embyonic fibroblast with almost undetectable levels of APE1 was isolated. Three isogenic derivatives of this cell line that contain either of the control vector, the human APE1 cDNA, and mouse Ape1 cDNA were analyzed for their global gene expression using Affymetrix mouse ST 2.0 chip set. An important question that we wished to ask was how clusters of genes categorized based on the cellular activities (e.g., glycolysis, cell cycle) are regulated by the hAPE1 and mApe1. Because of the high amino acid sequence similarity between the human and mouse APE1 (94% identical), the two proteins are expected to influence the globl gene expression similarly. Total RNA from a unique mouse embryonic fibroblast (MEF) line whose Ape1 expression is extremely low (0.2% of normal MEF). This is due to its genetic manipulation by transgenic procedures. The genotype of the APE1 gene in the MEF is mApe1-/- and hAPE1 transgenic (hAPE1TG). Mice used in this study were isogenic to C56BL/6.