Emergence of abnormal spindle networks in cells constitutively expressing HCMV UL76. (A) Representative images of mitotic spindles in empty vector-transfected and UL76-expressing cells, within which normal mitotic bipolar spindles (i) and abnormal monopolar, tripolar and tetrapolar spindles are evident (ii to iv), respectively. The mitotic spindle networks were visualized by using immunofluorescent staining of α-tubulin (red) and the chromosomal alignments were visualized by staining with DAPI (blue). Two side-by-side panels of single labeled immunofluorescent images and a third panel with an overlapping image are shown. (B) Quantification of mitotic spindles in cells stably expressing HCMV UL76 (S1, S3, S4, and S5) and control vector (P7).