The v- and c-myc oncogene proteins colocalize in situ with small nuclear ribonucleoprotein particles.

The intranuclear distribution of the v-myc and c-myc oncogene proteins were studied by immunofluorescence and immunoelectron microscopy. The nuclear distribution pattern of these proteins is shown to be identical to the distribution of small nuclear ribonucleoprotein particles (snRNPs). Colocalization was observed in cells expressing either the v- or c-myc proteins or in cells microinjected with the recombinant human c-myc protein. Immunolocalization studies revealed the v-myc protein and snRNPs to be concentrated within a nuclear network which excludes the nucleolus, nuclear pore-lamina complex, and portions of the nucleoplasm which contain the bulk of DNA. These results identify a nuclear region enriched in the myc-oncogene protein and snRNPs and raise the possibility that these nuclear constituents may function in related processes.