Quantitative analyses of process number and length on cultured hippocampal neurons at different developmental stages overexpressing katanin P80, con80, and P60. A-D, Immunostaining of EGFP for the cells that were transfected with the various constructs using EGFP as the tag. These cells were plated for 1 d, transfected, and allowed to express for 1 d. E-H, Quantification of data on the levels of katanin P80, con80, and P60 in the cell body, on process length, and on process number in hippocampal cultures at various days after plating, induced to express EGFP, P80-katanin, P60-katanin, or con80. The constructs were expressed for only 1 d after various days in culture. Day 1 refers to cells that were transfected before plating. Note that day 2 represents a particularly sensitive developmental stage with regard to process number. The P60 construct diminishes process number, whereas the P80 constructs increase process number (A-D, H) (p < 0.05 between control and P80/con80; p < 0.0001 for control and P60). With regard to the length of the processes, P80 and P60 overexpression decreased total process length by 30 and 50%, respectively (p < 0.01). Day 4 is sensitive in terms of process number and length, with all constructs diminishing both (p < 0.01). The number of days in culture is shown on the x-axis. The y-axis shows the total length of all of the processes extended by the neuron in micrometers (n > 20). At all time points, overexpression of P80 and con80 increases the protein level within the cell body by 2.3 times, whereas P60 increases total levels by ∼33% (E, F) (y-axis is in AFUs). Scale bar, 30 μm.