Fig. 7. Proliferation and differentiation in E12.5 wild-type and mutant dissociated cortical cell cultures between 12.75 and 24 hours after plating (all values are means±s.e.m.). (A) Percentages of BrdU-positive cells after a 45 minute pulse given 12 hours after plating. Significant differences (P<0.01) were observed between cultures of wild-type and mutant cells at all time-points from 12.75 hours after plating. (B) Cell density in cultures. Significant differences (P<0.01) were observed between cultures of wild-type and mutant cells at all time-points from 12.75 hours after plating. Regression analysis showed that the rate of increase for the mutant cells was just over twice that for the wild-type cells (r²=0.88 for Pax6^Sey/Sey and 0.99 for wild type). (C,D) Percentages of cells expressing cyclin A (C) and p27kip1 (D). Wild-type cells show no significant change in the number of cells expressing cyclin A and p27kip1 over the culture period (r²=0.07 for wild-type data in C and 0.22 for wild-type data in D). There is a significant decrease in the percentage of mutant cells expressing cyclin A in culture (r²=0.84). The percentages of Pax6^Sey/Sey cells expressing p27kip1 increase with time (r²=0.99).