Characterization of Pales spermatocyte spindles, with reference to an MTOC-associated protein.

Pales ferruginea spermatocytes, because of their high proportion of dividing cells, offer many advantages in the study of the meiotic spindle. In the present study we have combined ultrastructural and immunofluorescence techniques with biochemical analysis of constituent spindle components. Using a centrosome-reactive serum, which recognizes an antigen in the centrosomal and midbody regions of dividing cells, we have identified an MTOC-associated polypeptide of 112,000 Mr with a pI of 5.6. The relative abundance of this protein in cells and isolated cytoskeletons indicates that it is present in other regions of the cell and is either more abundant, or is only recognized by the antibody in association with MTOCs.