Figure 1.

Influence of ATM on IGF-IR expression. (A) Western blot analysis of IGF-IR expression levels in AT mutant, heterozygous, and wild-type human cells. All cells are SV40-transformed fibroblasts, except 3487 and 3489, which are primary fibroblasts from an affected individual and his heterozygous parent. (B) Analysis of ATM and IGF-IR expression in GM5849 cells, an SV40-transformed human fibroblast cell line from an AT individual, and a series of subclones transfected with wild-type ATM cDNA. ATM expression was determined by immune precipitation with anti-ATM antibody, followed by Western blot analysis with the same antibody. IGF-IR expression was determined directly by Western blot. (C) Confirmation of functional complementation of GM5849 cells by ATM cDNA expression based on radiation response. Clonogenic survival was determined following IR in the ATM-deficient GM5489 cells and in two subclones (5849cA2 and 5849cA4), transfected with a vector expressing the wild-type ATM cDNA. Also included for comparison is an unrelated wild-type cell line, GM637.