The inhibitor of growth (ING) family of type II tumor suppressors (ING1-ING5) are
involved in various cellular processes including apoptosis, DNA repair and tumor growth.
INGs are subunits of histone deacetylase (HDAC) and histone acetyltransferase (HAT)
complexes. The Drosophila genome encodes 3 ING homologues, dING 2, 3 and 4. In this
research, I showed that overexpression of dING2 leads to smaller tissue and clone size in
Drosophila. dING2 was sufficient to induce caspase-dependent but p53-independent cell
death, which promoted expression of the pro-apoptotic gene, reaper. Experiments
conducted on polyploid tissues revealed that clonal overexpression of dING2 had little
effect in cells in the larval fat body, but resulted in smaller salivary glands.
My experiments established that overexpression of dING3 induces caspase-dependent
cell death. However, neither dING2 nor dING3 is required for IR-induced apoptosis.
This work should provide valuable insights into the role of INGs in apoptosis.