p19INK4D PARTICIPATES IN THE CELL CYCLE ARREST INDUCTION IN RESPONSE TO NGF AND DNA DAMAGE

VARONE, C L; CERUTI, J M; CÁNEPA, E T

Córdoba, Argentina.

Congreso; XXXVII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2001

SAIB

The cyclinD/CDKs regulate G1 progression in response to a variety of extracellular signals. The activities of the cyclinD/CDKs can be negatively regulated by INK4 proteins, which act as specific inhibitors of CDK4/6. A key event during differentiation is the withdrawal from the cell cycle. DNA damage also induces alterations in cyclin D1/CDK4 activity. Such perturbations may contribute to G1 arrest following DNA injury.  In this study, we have investigated whether p19INK4d is involved in the response to differentiation and to DNA damage. To determine the role of p19 in differentiation, PC12 cells were treated with NGF in presence or absence of a p19 antisense oligonucleotide (ONp19). Thymidine incorporation was inhibited by NGF and FACS analysis revealed a G1 arrest. NGF treatment also resulted in neurite extension of 77% of the cells. On the contrary, ONp19 increased 80% thymidine incorporation, FACS profile returned to one similar to proliferating cells and the neurite extension decreased to 26%. On the other hand, HeLa and NIH3T3 cells were transfected with p19 expression vector or ONp19, respectively, and irradiated with UV. UV caused a clearly G1 arrest in p19 transfected HeLa cells, as shown by FACS analysis, diminished metabolic activity and induced cell survival. In contrast, UV irradiated NIH3T3 did not present significant changes in ONp19 treated cells. Our results suggest that p19INK4d could be involved in the cellular response to DNA damage and in the mechanism of differentiation in a cell-specific manner.