P34CDC2 KINASE HOMOLOG IN THE PREPROPHASE BAND

Immunofluorescence microscopy with a monoclonal antibody raised against the PSTAIR sequence, which corresponds to a peptide conserved in the p 34cdc2 protein kinase throughout the phylogenetic scale including higher plants, was used to study the intracellular localization of p 34cdc2 during the cell cycle in onion root tip cells. Although p 34cdc2 was evenly distributed in the cytoplasm throughout the cell cycle, a more intense staining was observed in the cortical region, where the preprophase band of microtubules (MTs) was located. Double staining with the PSTAIR and plant tubulin antibodies showed that the width of p 34cdc2 band was narrower than that of MT band. These data raise the interesting question regarding the possible role of p 34cdc2 protein kinase in determining the division site in plant cells.