Maize β-tubulin are encoded by a large multigene family with at least nine members, as determined by Southern blot analysis. Two expressed genes, represented by the β1 genomic clone and the β2 cDNA clone, were examined in this study. The two genes encode β-tubulins which show 94% sequence identity at the amino acid level. Maize β1 transcript levels were highest in seedling root tip and tissue culture cells, which are both rapidly dividing tissues. No transcripts were detected in non-dividing leaf tissue. In contrast, β2 transcripts were present at relatively high levels in tissue culture cells and at lower levels in seedling root tip and leaf tissue. The electrophoretic mobility of the β2 polypeptide was examined in relation to the constellation of β-tubulin polypeptides on two-dimensional gel western blots of a maize pollen total protein extract. No evidence for post-translational modification of the β-tubulin polypeptides was found in pollen.
- differential gene expression
- multigene family
- post-translational modification