Fig 4. Immunochemical labelling of the endogenous proteins PPAT and PAICS in CR-GART cells transfected with constructs encoding wt-GART proteins.

In cells transfected with constructs encoding the wt-GART protein, the endogenous proteins PPAT (A) and PAICS (B) were observed in the form of fine granules with their fluorescent signals showing a high degree of overlap in purine-depleted medium (C), whereas in purine-rich medium, the proteins PPAT (G) and PAICS (H) remained diffuse and did not colocalize (I). The same behaviour was observed in the control HeLa cells (Fig 9). Endogenous proteins in the non-transfected cells remained diffuse regardless of the level of purines in the media (D, E, J, K) and did not colocalize (F, L). The values of the fluorescent signal overlaps are shown in pseudocolour, and the scale is shown at the lower right in the corresponding LUT.