Fig. 1. Cdk5 is necessary for the differentiation of FBD-102b cells. (A) After induction of differentiation, FBD-102b-cell morphology was observed using phase-contrast microscopy. Representative images of cells are shown. (B) FBD-102b cells were randomly selected and assigned to one of three categories of complexity; low (two or less primary processes longer than a cell body, minimal development of secondary and tertiary processes), medium (three or more primary processes, moderate development of secondary and tertiary processes), and high (five or more primary processes, extensive development of secondary and tertiary. The percentagees of the cells in each category and the representative images of cells are shown. (C) FBD-102b cells were stained with antibodies against NG2 (green) or MBP (red) before or 4 days after induction of differentiation. (D) After induction of differentiation, FBD-102b cells treated with or without 10 µM roscovitine were lysed and immunoblotted with antibodies against MBP, PLP1 and β-actin. (E) RT-PCR analyses for MBP, PLP1, and β-actin were performed on differentiating cells treated with or without 10 µM roscovitine. (F) Representative images of cells treated with or without 10 µM roscovitine 4 days after induction of differentiation. The percentages of the cells in each category are shown in the bar graph. (G) The number of processes of the cells transfected with siRNAs for Cdk5 and luciferase is shown (left). Lysates from the transfected cells were immunoblotted with antibodies against Cdk5, paxillin and β-actin (right). Data were evaluated using Student's t-test (^*P<0.01).