NL4-3 miR viruses express miRNA in human cells. 293T cells were seeded in a 6-well plate and transfected with 2 μg pNL4-3 let7 scr, pNL4-3 let7a, pNL4-3 miR28, pNL4-3 miR29b, pNL4-3 miR138, pNL4-3 miR211, pNL4-3 miR326 and pNL4-3 miR329. RNA was extracted at 48 hours post transfection and used to determine miRNA levels using qPCR. Copy number per cell was determined based on normalization to miR16 and the assumption of 10 pg of RNA per cell. Each graph shows the expression of a specific miRNA after transfection of the indicated chimeric NL4-3 molecular clone. * indicates a p-value < 0.05 and ** indicates a p-value < 0.01.