Tubulin isoform usage in maize microtubules

Antibodies specific to two of the maize beta-tubulin isoforms and to the three subfamilies of maize alpha-tubulins were used in immunofluorescence microscopy to determine where and into which microtubule (MT) arrays these tubulin isoforms are incorporated in maize plants. All the tubulins examined appear to be incorporated into MTs in at least some cell types, with the possible exception of subfamily II alpha-tubulins, which have been found only in the form of diffuse, nonfibrillar staining. Whereas the alpha-tubulins of subfamily I appear to be used constitutively, others are used much more selectively in the plant, with beta 2-tubulin found in microtubules only during sexual reproduction. If a particular tubulin is used in the MTs of a given cell type, it appears to be incorporated into all the MT arrays found in the cell.