Molecular cloning and characterization of a cDNA clone that encodes a Cdc2 homolog from Nicotiana tabacum.

We have isolated a cDNA clone (cdc2Nt1) that encodes a homolog of p34(cdc2/CDC28) kinase from tobacco (Nicotiana tabacum). The cdc2Nt1 protein showed extensive similarity to other homologs of Cdc2 from plants. Complementation studies showed that the cdc2Nt1 gene was able to overcome cell cycle arrest at both the G1/S and the G2/M transitions of cdc28ts mutants of budding yeast, demonstrating that the cdc2Nt1 protein was able to replace the Cdc28 kinase at both the G1/S and the G2/M transitions. Analysis of gene expression demonstrated that the cdc2Nt1 gene was transcribed constitutively throughout the cell cycle but that it was preferentially expressed in activity dividing tobacco BY-2 cells.