ALTERED EXPRESSION OF A NOVEL CELLULAR GENE AS A CONSEQUENCE OF INTEGRATION OF HUMAN T-CELL LYMPHOTROPIC VIRUS TYPE-1

By analysing a genomic DNA clone derived from the human T cell lymphot ropic virus type 1 (HTLV-1)-infected cell line, TL-Su, we found that a n integrated HTLV-1 provirus interrupted the poly(A) signal-containing exon of a novel gene, RY-1. Nucleotide sequence analysis of a cDNA de rived from Jurkat cells revealed that the normal RY-1 mRNA could encod e a novel protein that has an unique primary structure, suggesting tha t a nucleic acid binding property was involved. Proviral integration l ed to an accumulation of aberrant RY-1 mRNA species in the cells. All the aberrant RY-1 cDNAs derived from TL-Su cells terminated at the pol y(A) site of the R region of the HTLV-1 long terminal repeat and initi ated in the intron, approx. 800 bp upstream from the putative second e xon. Furthermore, another intron, downstream from this position, remai ned unspliced in some of the cDNAs. In addition to the activation by t he integrated viral elements of cryptic promoters located upstream, me chanisms involving altered rates of degradation or transport from the nucleus to the cytoplasm of intron-containing RNA were suggested.