Gene profiling experiments reveal a dissociation between proliferation and effector functions in maturing NK cells. Gene expression profiles of sorted NK-cell subsets (n = 2 for each subset) were generated using pan-genomic microarrays. (A) Differentially expressed genes were identified and clustered according to their expression profile. The different clusters were numbered I to V. (B) A gene ontology analysis was performed on genes of the clusters I and IV. Highly significant terms are shown with the associated genes (boxes) and their expression profile in the 3 NK-cell subsets.