The human T-cell leukemia virus type 1 transactivator protein Tax colocalizes in unique nuclear structures with NF-kappaB proteins

F Bex, A McDowall, A Burny, R Gaynor
1997 Journal of Virology  
The Tax protein of human T-cell leukemia virus type 1 (HTLV-1) is a potent activator of viral transcription. Tax also activates the expression of specific cellular genes involved in the control of T-lymphocyte growth via effects on cellular transcription factors, including members of the NF-B/cRel family. Immunocytochemistry and electron microscopy were used to characterize the intracellular localization of Tax and identify cellular factors which are the potential targets for its
more » ... its transcriptional activity. These studies indicated that Tax localizes in discrete nuclear foci in T lymphocytes transformed by HTLV-1 and in cells transduced with Tax expression vectors. The Tax-containing foci are complex nuclear structures comprising a central core in which Tax colocalizes with splicing factor Sm. In addition to splicing factors Sm and SC-35, the Tax-containing nuclear structures also contain transcriptional components, including the largest subunit of RNA polymerase II and cyclin-dependent kinase CDK8. The inclusion of the two subunits of NF-B, p50 and RelA, and the presence of the mRNA from a gene specifically activated by Tax through NF-B binding sites suggest that these unique nuclear structures participate in Tax-mediated activation of gene expression via the NF-B pathway.
doi:10.1128/jvi.71.5.3484-3497.1997 fatcat:2aygonlzjjdz3akvse3k4nwayq