Fig. 1 Evaluation of the accumulated amount of neurofilament proteins and transcripts in transgenic and control samples. (A) A typical western blot of brain and spinal cord crude extracts from control (–) and transgenic (+) mice was revealed using antibodies against NFH, NFM and NFL. A much lower amount of each subunit was regularly found in transgenic samples. (B-B') The levels of NFHLacZ mRNA (B') were found to be between 12- and 80-fold lower compared with the endogenous NFH mRNA (B). No major difference in the expression of the endogenous NFH gene was observed between control and transgenic mice during ageing. (C) A 10-fold lower level of NFM mRNA was detected in brain compared with spinal cord without significant difference between control and transgenic tissues. (D-D') A similar pattern of expression of NFL was found between control and transgenic samples. In spinal cord, a 4-fold increase of the light transcript (2.5 kb) has been observed between the earlier stage of life and the other stages.