Tubulin isoform usage in maize microtubules

Antibodies specific to two of the maize beta-tubulin isoforms and to the th ree subfamilies of maize alpha-tubulins were used in immunofluorescence mic roscopy to determine where and into which microtubule (MT) arrays these tub ulin isoforms are incorporated in maize plants. All the tubulins examined a ppear to be incorporated into MTs in at least some cell types, with the pos sible exception of subfamily II alpha-tubulins, which have been found only in the form of diffuse, nonfibrillar staining. Whereas the alpha-tubulins o f subfamily I appear to be used constitutively, others are used much more s electively in the plant, with beta 2-tubulin found in microtubules only dur ing sexual reproduction. If a particular tubulin is used in the MTs of a gi ven cell type, it appears to be incorporated into all the MT arrays found i n the cell.