ANTISENSE INHIBITION OF GAS, THE HUMAN HOMOLOG OF THE YEAST CHROMOSOME SEGREGATION GENE CSE1, INTERFERES WITH MITOSIS IN HELA-CELLS

We have analyzed the effects on HeLa cells of reduction of the CAS pro tein, the human homologue to yeast chromosome segregation protein CSE1 . Expression of CAS antisense cDNA decreases the amount of CAS protein in HeLa cells and perturbs progression from G2 (retards transition fr om G2) to G1 in the cell cycle. Increased levels of cyclin B in CAS an tisense transfected cells correlated with an arrest in G2 phase or mit osis. This arrest upon CAS attenuation is consistent with observations that yeast with CSE1 mutations are defective in mitosis and cyclin B degradation.