The localization of the divergent beta 2-tubulin isotype in the microtubular arrays of Physarum polycephalum.
The beta 2-tubulin isotype of Physarum polycephalum is only 83% identical in amino acid sequence with the constitutively expressed beta 1B-tubulin and the myxamoeba-specific beta 1A-tubulin isotypes. A polyclonal antibody specific for beta 2-tubulin was used to monitor the subcellular distribution of the beta 2-tubulin antigen in the mitotic spindle of the mature plasmodium - the sole microtubular array in that stage of Physarum. By immunofluorescence, the beta 2-tubulin antigen was detected throughout this anastral mitotic spindle, at all stages of mitosis. Physarum myxamoebae contain astral mitotic spindles and cytoskeletal microtubules. No beta 2-tubulin antigen was detected in the myxamoebal stage. However, as cultures of myxamoebae developed into plasmodia, the beta 2-tubulin antigen was found in the astral mitotic spindles and cytoskeletons in developing cells. Thus, the presence of the plasmodial beta 2-tubulin isotype in a mitotic spindle does not determine a closed, anastral mitosis.
Diggins-Gilicinski
M
M
McArdle Laboratory for Cancer Research, University of Wisconsin, Madison 53706.
Solnica-Krezel
L
L
Burland
T G
TG
Paul
E C
EC
Dove
W F
WF
D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D008870:Microtubules / Q000276:immunology / Q000648:ultrastructure*; D008938:Mitosis; D010804:Physarum / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure*; D011506:Proteins; D014404:Tubulin / Q000032:analysis* / Q000276:immunology
D011506:Proteins; D014404:Tubulin