Table 1

Proliferation assays with heterozygous and homozygous N-CAM knockout astrocytes

ReagentConcentrationHeterozygous N-CAM knockout cells (−/+) Homozygous N-CAM knockout cells (−/−)
[3H]thymidine incorporation, % of control[3H]thymidine incorporation, % of control
N-CAM5 μg/ml30  ±  1101  ±  8
N-CAM2 μg/ml57  ±  7115  ±  2
Ig III3 μg/ml29  ±  494  ±  5
Ig III1 μg/ml33  ±  2106  ±  3
  • Astrocytes were obtained from transgenic mice that were heterozygous or homozygous for the disrupted N-CAM allele. N-CAM mRNA and protein was not detected in homozygous astrocytes (13). The amount of [3H]thymidine incorporation is presented as the percent incorporated compared to astrocytes treated with PBS alone. Addition of N-CAM or Ig III recombinant protein decreased the amount of [3H]thymidine incorporation in heterozygous but not homozygous astrocytes. Data are presented as mean ± SD (n = 4 for each condition).