Involved in regulation of the growth and differentiation transition (GDT) process, probably by regulating gene expression via histone modification. Interacts with H3K4me3 and to a lesser extent with H3K4me2. Constitutively expressed at low level throughout development (at protein level). The PHD-type zinc finger mediates the binding to H3K4me3. Cells provided with nutrients proliferate slower than normal. Upon starvation, the progression of differentiation is delayed in a cell density-dependent manner. Cells form tiny aggregates and more aggregation centers compared to wild-type cells, resulting in a higher number of tiny migrating slugs. Cells form complete tiny fruiting bodies 3-4 h faster than wild-type. In a similar manner to wild-type, most cells remain as non-aggregated single cells in the presence of caffeine, which is an inhibitor of adenylate cyclase activation. Decreased expression of cyclic AMP receptor carA gene and of csaA, a contact site A gene, both of which are expressed early in development. Cells exhibit a disordered change of histone H2B modification compared to wild-type, in which the modification level of histone H2B appears to increase in response to cell differentiation. Adequate histone H1 and H3 modifications are also impaired. Normal uniform distribution of starved cells in aggregation streams, but abnormal distribution of cells in subsequent multicellular structures. Belongs to the ING family.