Astrocyte primary cilia display distinct stages of ciliogenesis. (A) Astrocyte primary cilia ciliogenesis can be divided into five stages as show in the electron micrographs. The double headed arrows indicate that the stages of ciliogenesis displayed by individual astrocytoma/glioblastoma cell lines. At one extreme, T98G glioblastoma/glioblastoma multiforme cells never appear to initiate ciliogenesis, while the other cell lines progress to varying stages. (B) Electron micrographs illustrating representative images from four of the cell lines. 1) Early stage 1 common to U-373 MG, 2),3) and 5) are examples of misshaped or swollen vesicles in U-373 MG, U-138 MG and U-251 MG cells, 4) two centrioles in the same cell arrested at stage 2 in U-251 MG cells, 6) and 7) are examples of unusual ciliary buds in U-251 MG and U-373 MG cells, and 8) show an atypical and rare case of an early axoneme in U-87 MG cells.