Use of monoclonal antibodies to analyse the expression of a multi‐tubulin family

We have used a panel of monoclonal antibodies in a study of the expression of multiple tubulins in Physarum polycephalum. Three anti-β-tubulin monoclonal antibodies, DM 1B, DM3B3 and KMX-1 all reacted with the β₁-tubulin isotypes expressed in both myxamoebae and plasmodia. However, these antibodies showed a spectrum of reduced reactivity with the plasmodial β₂-tubulin isotype - the competence of recognition of this isotype was graded DM1B > KMX-1 > DM3B3. The anti-α-tubulin monoclonal antibody, YOL defined the full complement of Physarum α-tubulin isotypes, whilst the anti-α-tubulin monoclonal antibody, KMP-1 showed a remarkably high degree of isotype specificity. KMP-1 recognises all of the myxamoebal α₁-tubulin isotypes but only recognises 3 out of the 4 α₁-tubulin isotypes expressed in the plasmodium (which normally focus in the same 2D gel spot). KMP-1 does not recognise the plasmodial specific α₂-tubulin isotype. This monoclonal antibody reveals a new level of complexity amongst the tubulin isotypes expressed in Physarum and suggests that monoclonal antibodies are valuable probes for individual members of multi-tubulin families.