THE PLANT CELL, Vol 5, Issue 9 1101-1111, Copyright © 1993 by American Society of Plant Biologists
Localization of the Functional p34cdc2 Homolog of Maize in Root Tip and Stomatal Complex Cells: Association with Predicted Division Sites
J. Colasanti, S. O. Cho, S. Wick and V. Sundaresan
Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, 11724
We have used an antibody against the functional homolog of the cdc2 kinase
of maize to localize the p34cdc2 protein within dividing cells of the root
apex and the stomatal complex of leaf epidermis. The microtubule
cytoskeletal structure of plant cells was visualized concomitantly with a
monoclonal antibody specific for [alpha]-tubulin. We found that the cdc2
protein is localized mainly to the nucleus in plant cells at interphase and
early prophase. This finding contrasts markedly with the predominantly
cytoplasmic staining obtained using antibody to the PSTAIRE motif, which is
common to cdc2 and numerous cdc2-like proteins. In a subpopulation of root
cells at early prophase, the p34cdc2 protein is also distributed in a band
bisecting the nucleus. Double labeling with the maize p34cdc2Zm antibody
and tubulin antibody revealed that this band colocalizes with the
preprophase band (PPB) of microtubules, which predicts the future division
site. Root cells in which microtubules had been disrupted with oryzalin did
not contain this band of p34cdc2 protein, suggesting that formation of the
microtubule PPB is necessary for localization of the p34cdc2 kinase to the
plane of the PPB. The p34cdc2 protein is also localized to the nucleus and
PPB in cells that give rise to the stomatal complex, including those cells
preparing for the highly asymmetrical divisions that produce subsidiary
cells. Association of the p34cdc2 protein with the PPB suggests that the
cdc2 kinase has a role in establishing the division site of plant cells
and, therefore, a role in plant morphogenesis.
