ISOLATION AND CHARACTERIZATION OF A FUNCTIONAL A-TYPE CYCLIN FROM MAIZE

Cyclins are involved in the regulation of cell cycle progression in eu karyotes. We have isolated a cyclin cDNA clone, cycZm2w, from maize ro ot tip cells, which fits best into group A2 of current plant cyclin ge ne classification schemes. The cDNA encodes a protein with a domain ho mologous to the cyclin box of mitotic cyclins. Complementation studies revealed that cycZm2w was able to rescue a budding yeast cyclin-defic ient mutant (BF305-15d#21). As expected, cycZm2w is expressed in organ s of the maize plant that possess meristematic activity, but is especi ally prominent in the proliferating regions of the root apex.