Chromosomal instability of fanconi anemia cells is not the consequence of a defective repair activity of the ribosomal protein S3.

Fanconi anemia (FA) is an autosomal recessive chromosomal breakage disorder characterized by developmental defects, hypersensitivity toward oxygen and DNA crosslinking agents, and susceptibility to cancer. An increased level of reactive oxygen intermediates and an increased level of 8-oxoguanine in FA cells point to a defective oxygen metabolism. Recent investigations showed that FA cells from several complementation groups have a reduced capacity to repair oxidatively damaged DNA. One major enzyme involved in the repair of oxidative DNA lesions is the ribosomal protein S3. Previous reports implied a role for the ribosomal protein S3 in DNA repair in FA cells. However, a more detailed analysis of the ribosomal protein S3 in FA cells from complementation groups A-E could not confirm this. DNA analysis and Western blot analysis did not show significant differences in ribosomal protein S3 between FA cells and cells from healthy individuals. Furthermore, even the overexpression of the ribosomal protein S3 did not reduce the chromosomal instability of FA cells.